errors

Errors in Node.js

Imagine your computer code as a recipe. Errors are like little mistakes in the recipe that can cause the whole thing to go wrong. Node.js has different types of errors:

1. Standard JavaScript Errors:

These are like spelling mistakes in your recipe. They happen when you make mistakes in how you write your code, like:

Forgetting a comma after an ingredient (SyntaxError)
Trying to use a variable that doesn't exist (ReferenceError)

2. System Errors:

These are like running out of butter or sugar when you're baking. They happen when there's a problem with the computer itself, like:

Trying to read a file that doesn't exist
Sending data over a closed connection

3. User-Specified Errors:

These are like when you deliberately make a mistake in your recipe, like adding too much salt. They're created by you in your code to tell your program when something unexpected happens.

4. Assertion Errors:

These are like when your recipe says "if it's not raining, go for a walk" and it's pouring outside. They happen when something that should never happen, like a missing ingredient, does.

Real World Examples:

JavaScript Error: Forgetting to close a parenthesis in a function definition would cause a SyntaxError.
System Error: Trying to read a file that doesn't exist would cause a ENOENT (Entity Not Found) error.
User-Specified Error: Throwing a new Error('No butter left!') error when you run out of butter in your recipe.
Assertion Error: Running assert.ok(isRainy) would throw an error if it's not raining.

Potential Applications:

Errors are crucial for handling unexpected situations and providing helpful information to developers and users. They allow:

Debugging and fixing code issues
Logging errors for analysis and troubleshooting
Protecting users from unexpected behavior
Providing error messages to guide users in resolving problems

Error Propagation and Interception in Node.js

Imagine Node.js as a big machine that runs your code. When something goes wrong, the machine tries to tell you about it by throwing an "error."

JavaScript Errors

JavaScript errors are like when you tell your computer to do something it can't understand. These errors happen right away and must be handled using a special command called try...catch.

Asynchronous Errors

Some code runs over time, like making a request to a website. If something goes wrong during this time, errors can be reported in three ways:

Promises: Promises are like special boxes that can hold a result (like the data from the website) or an error. You can tell your code to expect an error by checking if the promise is "rejected."
Callbacks: Some code uses "callbacks" to tell you when it's done. If there's an error, the callback will be called with the error as the first argument.
Events: Some code uses "events" to send messages. If an error happens, the code will send a message called an "'error' event." You can listen for this event to handle the error.

Synchronous Errors

Some code runs right away, like reading a file from your computer. If an error happens here, the machine will throw the error immediately. You must handle it with try...catch or the machine will stop running.

Example:

Let's say you have some code that reads a file called "file.txt":

try {
  const data = fs.readFileSync("file.txt"); // This code might throw an error
} catch (err) {
  // If an error happens, it will be caught here and you can handle it
}

Applications in the Real World:

Error handling is important to make sure your website doesn't crash when something goes wrong.
You can use error handling to provide helpful messages to your users.
By handling errors, you can prevent your code from stopping unexpectedly and keep your applications running smoothly.

Class: Error

An Error object is like a special kind of message that tells you something went wrong in your code. It's like when you're playing a game and you get stuck at a certain level. The Error object is like a message that tells you why you can't move forward.

Topics:

1. Stack Trace:

It's like a map that shows you the exact place in your code where the error happened. It's like a detective finding the exact spot where a crime took place.

2. Text Description:

Sometimes the Error object also has a message explaining what went wrong. It's like a note the detective leaves at the crime scene, telling you what happened.

3. Instances and Inheritance:

Every error in Node.js is either an Error object or related to it. It's like a family tree, where Error is the parent and all other errors are its children.

Real-World Examples:

When you try to open a file that doesn't exist, you'll get an Error object telling you the file doesn't exist.
When you try to add two numbers and you forget to add a plus sign, you'll get an Error object telling you there was a syntax error.

Applications:

Finding and fixing errors in your code
Debugging code to make sure it's working correctly
Writing custom error messages to help users understand what went wrong

Error(message, options)

The Error constructor creates a new Error object and sets the error.message property to the provided text message. If an object is passed as message, the text message is generated by calling String(message). If the cause option is provided, it is assigned to the error.cause property.

Simplified example:

const errorMessage = 'Something went wrong';
const error = new Error(errorMessage);

This creates a new Error object with the message "Something went wrong".

Real-world example:

try {
  // Some code that might throw an error
} catch (error) {
  // Handle the error
}

In this example, the try...catch block is used to handle errors that might occur while executing the code within the try block. If an error is thrown, it is caught by the catch block and assigned to the error variable. The error message can then be accessed using error.message.

Potential applications

Errors are used to indicate that something has gone wrong during the execution of a program. They can be used for a variety of purposes, including:

Debugging: Errors can help developers identify and fix problems in their code.
Logging: Errors can be logged to a file or database for later review.
Reporting: Errors can be reported to users so that they can be informed of any problems that have occurred.

`Error.captureStackTrace(targetObject[, constructorOpt])`

Simplified Explanation:

Imagine you have a box of toys. You want to put a sticker on the box that says where you bought it.

Error.captureStackTrace() is like that sticker. It puts a note on an object called targetObject that says where the error came from.

You can think of constructorOpt as a special box. When you put the sticker on the box, you can tell it to skip putting the stickers on any boxes that are inside the special box.

Detailed Explanation:

What does targetObject do?

targetObject is the object you want to put the sticker on. This object can be anything, like a custom error object or even a regular JavaScript object.

What does constructorOpt do?

constructorOpt is an optional argument that lets you specify the starting point for the sticker. By default, the sticker includes the stack trace from the current function. But if you pass in a different function as constructorOpt, the sticker will start from that function and ignore any stack traces before it.

Real-World Example:

Let's say you have a function that calculates the area of a triangle:

function calculateArea(base, height) {
  if (base <= 0 || height <= 0) {
    throw new Error("Base or height must be greater than 0");
  }
  return 0.5 * base * height;
}

If you try to call this function with invalid inputs, like:

try {
  calculateArea(0, -1);
} catch (error) {
  console.log(error.stack);
}

The console.log statement will print the stack trace, which shows the exact line of code where the error occurred:

Error: Base or height must be greater than 0
    at calculateArea (/Users/johndoe/projects/math/triangle.js:6:11)
    at Object.<anonymous> (/Users/johndoe/projects/math/test.js:5:17)

In this case, the sticker is on the error object, and it shows that the error came from the calculateArea function at line 6.

Potential Applications:

Debugging: The stack trace helps developers identify the source of errors and understand how their code is running.
Custom error handling: You can use the stack trace to create custom error messages that include relevant information about the error.
Logging and reporting: The stack trace can be used to log errors and provide information to support teams or external services.

`Error.stackTraceLimit` Explained for a 5-Year-Old Child

Imagine a tall building with many floors. Each floor represents a step in the code that your computer takes.

When there's a problem in the code, the computer prints out a list of all the floors it went through before the problem happened. This list of floors is called a "stack trace."

Error.stackTraceLimit tells the computer how many floors to print when it creates a stack trace. The default is 10 floors, but you can choose any number you want.

Here's an example:

// Set the stack trace limit to 5 floors
Error.stackTraceLimit = 5;

// Create an error
const error = new Error("Oh no!");

// Print the stack trace
console.error(error.stack);

This will print the following stack trace:

Error: Oh no!
    at index.js:12:10
    at index.js:8:18
    at index.js:5:23
    at index.js:2:32
    at Object.<anonymous> (index.js:1:1)

As you can see, the stack trace only includes the first 5 floors, even though there are more.

Real-World Applications:

Debugging: Stack traces help developers understand where in the code a problem occurs. By setting Error.stackTraceLimit, developers can control how much detail they want in the stack trace.
Security: Stack traces can reveal sensitive information about your code, such as filenames and line numbers. By setting Error.stackTraceLimit to a small number, you can protect your code from unauthorized access.

What is error.cause?

error.cause is a way to store the original error that caused a new error to happen.

Why is error.cause useful?

Imagine you have a function that reads a file from the hard drive and then sends the contents of that file over the internet. If the file is not found, you want to send back a specific error message to the person who is trying to access the file. However, you also want to know that the original error was that the file was not found, so you can log that error to help you debug your program later.

How do I set error.cause?

You can set error.cause when you create a new error using the new Error() constructor. For example:

const originalError = new Error('File not found');
const newError = new Error('Could not send file', { cause: originalError });

How do I access error.cause?

You can access error.cause by using the dot operator, like this:

const cause = error.cause;

Real-world example

Here is a real-world example of how error.cause can be used:

function readFile(filename) {
  try {
    const data = fs.readFileSync(filename);
    return data;
  } catch (error) {
    // If the file was not found, create a new error with the original error as the cause
    if (error.code === 'ENOENT') {
      error = new Error('File not found', { cause: error });
    }

    // Throw the new error
    throw error;
  }
}

try {
  const data = readFile('myfile.txt');
} catch (error) {
  // Log the original error
  console.error(error.cause);
}

In this example, the readFile() function reads a file from the hard drive. If the file is not found, the function creates a new error with the original error as the cause. This allows us to log the original error to help us debug our program later.

Potential applications

There are many potential applications for error.cause. Here are a few examples:

Debugging: error.cause can help you debug your programs by providing you with the original error that caused a new error to happen.
Logging: error.cause can be used to log the original error to a file or database. This can be helpful for tracking down problems in your application.
Error handling: error.cause can be used to handle errors in a more specific way. For example, you could create a custom error handler that handles errors with a specific error.cause.

Error Codes in Node.js

What is an error code?

An error code is a string that identifies the type of error that has occurred. Error codes are useful for developers because they can help them to quickly identify and fix problems.

Why are error codes important?

Error codes are important because they provide a consistent way to identify and handle errors. This makes it easier for developers to write code that is robust and can handle unexpected situations.

How do I use error codes?

To use error codes, you can use the error.code property of an error object. The error.code property will contain a string that identifies the type of error that has occurred.

What are some common error codes?

Some common error codes include:

ENOENT: This error code indicates that a file or directory does not exist.
EACCES: This error code indicates that you do not have permission to access a file or directory.
EINVAL: This error code indicates that an invalid argument was passed to a function.
EMFILE: This error code indicates that the system has run out of file descriptors.

How can I find out more about error codes?

You can find out more about error codes by reading the Node.js error codes documentation.

Real-world example

The following code shows how to use error codes to handle errors:

try {
  // Do something that might throw an error
} catch (err) {
  if (err.code === "ENOENT") {
    // Handle the error by doing something else
  } else if (err.code === "EACCES") {
    // Handle the error by doing something else
  } else {
    // Handle the error in a generic way
  }
}

Potential applications

Error codes can be used in a variety of applications, including:

Debugging code
Writing robust applications
Handling errors in a consistent way

Error.message property

The error.message property is a string that describes the error. It is set when the Error object is created, and can be changed later.

Example:

const err = new Error("The message");
console.error(err.message);
// Prints: The message

Real-world applications

The error.message property is useful for debugging purposes. It can help you understand what caused the error, and how to fix it.

Example:

try {
  // Some code that might throw an error
} catch (err) {
  console.error(err.message);
}

In this example, the try...catch block catches any errors that are thrown by the code. The console.error statement prints the error message to the console, which can help you debug the problem.

The Error.stack Property

Imagine you have a program that has an error, like a car that breaks down. The error.stack property is like a map that shows you where the error happened in your program, just like a mechanic knows which part of the car broke down.

Stack Frames

The error.stack property lists all the places in your program where the error happened. Think of it like a stack of boxes, where each box represents a different part of your program. The top box is where the error happened, and the bottom box is the starting point of your program.

Each box has two parts:

The name of the function where the error happened
The line number and column number where the error happened

Example

function addNumbers(a, b) {
  return a + b;
}

addNumbers(1, 2); // Calls the function with the numbers 1 and 2

try {
  addNumbers(1, "2"); // Calls the function with the number 1 and the string "2"
} catch (error) {
  console.log(error.stack);
}

Output:

Error: Cannot add a number and a string
    at addNumbers (/path/to/script.js:5:10)
    at /path/to/script.js:10:5

In this example, the error happened in the addNumbers function, on line 5, column 10. The error was caused by trying to add a number and a string, which is not allowed in JavaScript.

Applications in the Real World

The error.stack property is useful for debugging errors in your programs. It can help you understand where the error happened and what caused it. This information can help you fix the error and prevent it from happening again.

Simplified Explanation:

An AssertionError is an error that happens when a program expects something to be true, but it's actually not. It's like when you're playing hide-and-seek and you think your friend is under the bed, but they're really in the closet.

Technical Details:

AssertionError is a special type of error in Node.js that indicates a failed assertion. An assertion is like a statement that says something should be true. If that statement turns out to be false, the AssertionError is thrown.

Real-World Example:

Let's say you have a function that checks if a number is even. You might have an assertion that says:

assert.equal(number % 2, 0);

This assertion means that the remainder of number divided by 2 should be 0 (i.e., number should be even). If this assertion fails, it means the function is not correctly checking for even numbers.

Potential Applications:

AssertionErrors are used in testing to make sure that your code is working correctly. They help you find errors early on, so you can fix them before they cause problems in production.

Code Implementation:

Here's a simple example of using AssertionError in Node.js:

// Define a function to check if a number is prime
function isPrime(number) {
  // Iterate through all numbers up to the square root of the given number
  for (let i = 2; i <= Math.sqrt(number); i++) {
    // If the number is divisible by any number up to its square root, it's not prime
    if (number % i === 0) {
      throw new AssertionError("The number is not prime.");
    }
  }

  // If the loop completes without finding any divisors, the number is prime
  return true;
}

// Test the isPrime function with different numbers
const numbers = [2, 3, 4, 5, 6, 7, 8, 9, 10];
for (const number of numbers) {
  try {
    const isPrimeResult = isPrime(number);
    console.log(`${number} is ${isPrimeResult ? "prime" : "not prime"}.`);
  } catch (error) {
    // If the isPrime function throws an AssertionError, log the error message
    console.error(error.message);
  }
}

This code defines an isPrime function that checks if a given number is prime. It then tests the function with various numbers using a try...catch block. If the isPrime function throws an AssertionError, the error message is logged to the console.

What is a RangeError?

Imagine you're playing a game where you have to roll dice that have numbers from 1 to 6. If you try to roll a die that has the number 7, you would get an error because 7 is not a valid value for the dice.

This is like the RangeError in programming. It happens when you give a function a number or value that it's not expecting or allowed to handle.

Example:

// This code tries to connect to a port number that is outside the range of 0 to 65535
const port = -1;
require("net").connect(port);

Output:

RangeError: "port" option should be >= 0 and < 65536: -1

In this example, the connect function expects a port number between 0 and 65535. But we gave it a value of -1, which is outside that range. So, it throws a RangeError.

Potential Applications:

RangeError is used to prevent invalid inputs from causing unexpected behavior or errors in your program. For example, it can be used to ensure that:

Database queries only return a specific number of results
Array indices are within bounds
Function parameters are within a certain range of values

Simplified Explanation in Plain English:

What is a ReferenceError?

Imagine you're playing with toy blocks and you want to find a block with a specific shape, like a triangle. You look all over, but you can't find it. You might say, "Triangle block doesn't exist!" That's like a ReferenceError. It means you're trying to access something (like a variable) that doesn't exist in your program.

How does it Happen in JavaScript?

For example, let's say you have a variable named "age", but you accidentally type it as "agee". When you try to use it, you'll get a ReferenceError because "agee" is not a real variable. It's like trying to find a toy block that doesn't exist.

Why is it Important?

ReferenceErrors help us find mistakes in our code. They tell us that there's something we're trying to use that doesn't exist. This helps us fix our code and make sure it works properly.

Real-World Example:

Imagine you're building a website and you want to show a user's profile picture. But you forgot to define the variable that stores the picture URL. When the website tries to display the picture, you'll get a ReferenceError because the variable doesn't exist. This lets you know that you need to add the variable to your code before the website can show the picture.

How to Avoid it:

To avoid ReferenceErrors, make sure you:

Double-check variable names for typos.
Define all variables before using them.
Use tools like code linters to help you find potential errors.

Simplified explanation of SyntaxError

A SyntaxError means that your JavaScript code has a mistake in it. It's like when you're writing a letter and you make a typo, like writing "teh" instead of "the." Your computer can't understand what you're trying to say and it doesn't know how to fix it.

Detailed explanation of SyntaxError

SyntaxError is one of the many types of errors that can happen when your JavaScript code is running. It's a special kind of error that means that there's something wrong with the way your code is written. It's not a problem with your computer or your browser, it's a problem with the code itself.

SyntaxErrors can be caused by many different things, such as:

Missing or extra punctuation, like forgetting to put a semicolon at the end of a line
Using the wrong keywords, like writing if instead of else
Using the wrong data types, like trying to add a string to a number

Code snippet

Here's an example of a JavaScript code that will cause a SyntaxError:

let x = 5 + "hello";

When you try to run this code, you'll get a SyntaxError. The error will say that you can't add a string to a number.

Real-world example

SyntaxErrors are very common in JavaScript, especially when you're first learning the language. It's important to be able to recognize and fix SyntaxErrors so that you can write code that runs correctly.

One real-world example of a SyntaxError is when you forget to put a semicolon at the end of a line. This will cause your code to fail when it's run.

Potential applications

SyntaxErrors can be used to help you debug your JavaScript code. By looking at the error message, you can usually figure out what's wrong with your code and fix it.

Another potential application of SyntaxErrors is to prevent your code from running if it's not valid. This can be useful for security purposes, because it can help to prevent malicious code from running on your computer.

Conclusion

SyntaxErrors are a common error in JavaScript, but they're easy to fix once you know what they are. By understanding the basics of SyntaxErrors, you can write code that runs correctly and is more secure.

SystemError

Imagine you're building a house and you realize you don't have the right tools to finish the job. That's kind of like a SystemError in Node.js. It happens when something goes wrong in the "runtime environment" (the tools for building the house), usually because you're asking the system to do something it can't handle.

Properties:

address: The address you're trying to connect to when there's a network problem.
code: A special code that describes the type of error.
dest: The file path you're trying to access when there's a file system issue.
errno: A number that gives you more information about the error.
info: Extra details about the error.
message: A simple explanation of the error.
path: The file path when there's a file system problem.
port: The port you're trying to connect to when there's a network issue.
syscall: The command you're trying to run when the error happens.

Real-World Example:

Imagine you're building a website and you try to access a file that doesn't exist. Your code will get a SystemError with a message like "ENOENT: no such file or directory." This tells you that the file you're looking for doesn't exist.

Applications:

SystemErrors are useful for handling errors that occur because of the operating system or the underlying environment, such as:

File system issues
Network problems
Resource allocation errors
Invalid system calls

Code Implementation:

Here's an example of how you can catch and handle a SystemError:

try {
  // Do something that might cause a SystemError
} catch (err) {
  if (err instanceof SystemError) {
    // Handle the SystemError
  } else {
    // Handle other types of errors
  }
}

`error.address`

This property is a string that describes the address to which a network connection failed.

For example, if you try to connect to a server at the address 127.0.0.1 and the connection fails, the error.address property of the error object will be set to 127.0.0.1.

This property can be useful for identifying the source of a network connection failure.

Real-world example

The following code snippet attempts to connect to a server at the address 127.0.0.1. If the connection fails, the error.address property of the error object will be set to 127.0.0.1.

const net = require("net");

const client = net.connect({ host: "127.0.0.1", port: 80 }, () => {
  // The connection was successful.
});

client.on("error", (err) => {
  // The connection failed.
  console.log(err.address); // Output: 127.0.0.1
});

Potential applications

This property can be used to identify the source of a network connection failure. This information can be used to troubleshoot and resolve the issue.

The error.code Property in Node.js

Simplified Explanation

Every error in Node.js has a special "code" that describes the type of error it is. It's like a label that helps us understand what went wrong.

Detailed Explanation

When something goes wrong in your Node.js code, an error object is created. This error object contains a bunch of information about the error, including a code property.

The code property is a string that represents the type of error. For example, if you try to read a file that doesn't exist, you might get an error object with a code property of ENOENT, which stands for "no such file or directory".

Real-World Examples

Here's an example of how you might use the error.code property in your code:

try {
  // Try to read a file that doesn't exist
  const data = fs.readFileSync("non-existent-file.txt");
} catch (error) {
  if (error.code === "ENOENT") {
    // Handle the error gracefully
    console.log("The file does not exist");
  } else {
    // Handle other types of errors
    console.log("An unexpected error occurred");
  }
}

In this example, we're trying to read a file called non-existent-file.txt. If the file doesn't exist, we'll get an error object with a code property of ENOENT. We can then handle the error gracefully, such as by displaying a message to the user.

Potential Applications

The error.code property can be used for a variety of purposes, such as:

Error handling: You can use the error.code property to distinguish between different types of errors and handle them appropriately.
Debugging: You can use the error.code property to help you track down the source of errors in your code.
Creating custom error classes: You can create your own custom error classes and assign them unique codes. This can make it easier to identify and handle errors in your code.

What is error.dest?

error.dest is a property of an error object that contains the file path where the error occurred. This information is helpful in debugging file system errors, such as when a file cannot be opened or read.

How to use error.dest?

To access the error.dest property, you can use the following code:

const error = new Error("File not found");
error.dest = "/path/to/file.txt";
console.log(error.dest); // '/path/to/file.txt'

Real-world example

Imagine you have a program that reads a file from disk. If the file cannot be found, the program will throw an error. The error.dest property will contain the path to the file that could not be found, which can help you debug the issue.

Potential applications

error.dest can be used in any program that works with files. It can help you debug file system errors and ensure that your program is handling file access correctly.

Error Codes in Node.js

What are error codes?

Error codes are numbers that represent specific errors that can happen in a computer program. They help us understand what went wrong and how to fix it.

Where can I find error codes in Node.js?

Node.js has a built-in property called error.errno that contains the error code for a specific error.

How do I use error.errno?

You can use it as follows:

const { exec } = require("child_process");

exec("ls /doesnotexist", (err, stdout, stderr) => {
  if (err) {
    console.error(`exec error: ${err.errno}`);
  }
});

Example error code:

If the file /doesnotexist does not exist, the error.errno will be:

-2;

Converting error codes to human-readable strings:

To make error codes easier to understand, Node.js provides a function called util.getSystemErrorName(). This function takes an error code and returns a human-readable string.

const { util } = require("util");

const errCode = -2;

console.log(util.getSystemErrorName(errCode)); // Output: "ENOENT"

Applications in the real world:

Error codes can be used to:

Identify and fix errors in your code
Provide helpful error messages to users
Log errors for later analysis

Additional Notes:

Error codes are negative numbers.
Error codes are standardized and can be found in the documentation for the operating system you are using.
Not all errors have error codes.

What is error.info?

In Node.js, when an error occurs, it can provide additional information about the error condition in an object called error.info. This information can be helpful in debugging and understanding what caused the error.

How to access error.info?

To access the error.info object, you can use the following code:

try {
  // Code that might throw an error
} catch (error) {
  console.error(error.info);
}

What kind of information can be found in error.info?

The information contained in error.info depends on the specific error that occurred. However, it typically includes details such as:

The error message
The stack trace (which shows the series of function calls that led to the error)
Any additional context information that can help identify the cause of the error

Real-world example

Consider the following code:

try {
  const result = divide(10, 0);
} catch (error) {
  console.error(error.info);
}

In this example, the divide() function is called with two numbers. However, the second number is 0, which results in a division by zero error. The error.info object would contain information about this error, including the error message and the stack trace:

{
  message: 'Cannot divide by zero',
  stack: 'Error: Cannot divide by zero\n    at divide (index.js:10:15)\n    at evaluation (index.js:17:7)'
}

This information can help us identify the cause of the error and fix it.

Applications in the real world

error.info can be useful in various real-world applications, such as:

Debugging: error.info can provide valuable insights into the cause of an error, making it easier to debug and fix.
Logging: The information in error.info can be logged to help track and analyze errors in a production environment.
Error handling: error.info can be used to create custom error handling mechanisms that provide more detailed and user-friendly error messages.

What is error.message?

error.message is a message that describes the error that happened. It's like a note that the computer writes to help you understand what went wrong.

How does it look like?

error.message can look something like this:

"Error: File not found"

This message tells us that the computer couldn't find a file that it was looking for.

Why is it useful?

error.message is useful because it helps us understand what went wrong and how to fix it. For example, if we see the message "Error: File not found", we know that we need to make sure that the file exists and that the computer can find it.

Real-world example

Imagine you're writing a program that reads data from a file. If the file doesn't exist, the program will raise an error with the message "Error: File not found". You can then use this message to tell the user that the file doesn't exist and ask them to choose a different file.

Potential applications

error.message is used in many different applications, such as:

Debugging: To help developers understand what went wrong in their code.
Logging: To store error messages so that they can be reviewed later.
User feedback: To provide helpful error messages to users so that they can fix the problem.

error.path

The error.path property is a string that contains a relevant invalid pathname if one is present. A pathname is the part of a URL that specifies the location of a resource. For example, in the URL https://example.com/index.html, the pathname is /index.html.

If an error occurs while trying to access a resource, the error.path property will contain the invalid pathname. This can be useful for debugging purposes.

Example:

try {
  fetch("https://example.com/non-existent-file.html");
} catch (error) {
  console.error(error.path); // '/non-existent-file.html'
}

Real-world applications:

Debugging errors that occur when trying to access resources
Identifying invalid pathnames in URLs
Providing useful error messages to users

Simplified Explanation:

error.port

When trying to connect to a network, sometimes the port that is being used is not available. When this happens, an error occurs and the error.port property contains the port number that was not available.

Example:

const net = require('net');

const server = net.createServer((socket) => {
  socket.on('data', (data) => {
    console.log(data.toString());
  });
});

server.listen(80, () => {
  console.log('Server listening on port 80.');
});

// Try to connect to the server on a different port.
const client = net.connect({ port: 81 }, () => {
  client.write('Hello, world!');
});

client.on('error', (error) => {
  if (error.code === 'ECONNREFUSED') {
    console.log('Port 81 is not available.');
    console.log(`Error.port: ${error.port}`);
  }
});

Output:

Server listening on port 80.
Port 81 is not available.
Error.port: 81

Real-World Application:

Checking if a specific port is available before starting a server or connecting to a service.

What is error.syscall?

error.syscall tells you which system call (also known as a "syscall") caused the error. A syscall is a way for a program to talk to the operating system (the software that controls your computer).

How do I use error.syscall?

You can use error.syscall to find out what went wrong when a program crashes. For example, if you try to open a file that doesn't exist, you might get an error.syscall like this:

error.syscall: 'open'

This tells you that the error happened when the program tried to open the file.

Real-world example

Here's a simple program that tries to open a file that doesn't exist:

const fs = require("fs");

try {
  fs.readFileSync("myfile.txt");
} catch (err) {
  console.log(`Error: ${err.message}`);
  console.log(`Syscall: ${err.syscall}`);
}

Output:

Error: ENOENT: no such file or directory, open 'myfile.txt'
Syscall: 'open'

Applications

error.syscall can be used to help diagnose and fix errors in your programs. For example, you could use it to:

Find out what syscall caused a program to crash
Figure out why a file open failed
Track down network connection issues

Simplified explanation for a 5-year-old child

Imagine your computer is like a big playground, and there are lots of different things you can do on the playground. Sometimes, when you try to do something, you might have to ask the playground supervisor for help. If something goes wrong, the playground supervisor will tell you what happened.

The error.syscall is like the playground supervisor's report. It tells you what you were trying to do when the error happened, so you can figure out what went wrong.

Common System Errors in Node.js

Permission Denied (EACCES)

Your program doesn't have access to a file or folder you're trying to use. Imagine trying to open someone else's bedroom door without permission.

Address Already in Use (EADDRINUSE)

You're trying to connect a server to a specific address that's already being used by another server. Think of trying to connect two water hoses to the same faucet at the same time.

Connection Refused (ECONNREFUSED)

The server you're trying to connect to is not running or blocking your connection. It's like trying to call someone who has their phone turned off.

Connection Reset by Peer (ECONNRESET)

The other side of the connection has suddenly closed it. It's like someone hanging up the phone on you in the middle of a conversation.

File Exists (EEXIST)

You're trying to create a file that already exists, kind of like trying to paint over something that's already painted.

Is a Directory (EISDIR)

You're trying to use a directory (like a folder) as if it were a file (like a document). Imagine trying to use a box of crayons to write a letter.

Too Many Open Files (EMFILE)

Your program has opened too many files at the same time. Think of trying to carry 1,000 grocery bags at once.

No Such File or Directory (ENOENT)

The file or folder you're looking for doesn't exist. It's like trying to find a book in your library that doesn't have a title.

Not a Directory (ENOTDIR)

You're trying to use a file as if it were a directory. Imagine trying to open a book like it's a drawer.

Directory Not Empty (ENOTEMPTY)

You're trying to delete a directory that has files or folders in it. Think of trying to remove a box from a shelf that has other boxes on it.

DNS Lookup Failed (ENOTFOUND)

Your program can't find the IP address or domain name of the server you're trying to connect to. It's like trying to dial a phone number that doesn't exist.

Operation Not Permitted (EPERM)

Your program is trying to do something that requires special permissions, like writing to a file that only an administrator can write to. Imagine trying to drive a car without a license.

Broken Pipe (EPIPE)

The other side of the connection has closed it without properly ending it. It's like someone cutting the phone line while you're still talking.

Operation Timed Out (ETIMEDOUT)

Your program has waited too long for a response from the other side of the connection. Think of waiting for someone to answer the phone for so long that you give up and hang up.

Real World Code Examples:

// Permission Denied

try {
  fs.writeFile("secret.txt", "Top secret!");
} catch (err) {
  if (err.code === "EACCES") {
    console.log("You don't have permission to write to that file.");
  }
}

// No Such File or Directory

try {
  fs.readFile("missing.txt");
} catch (err) {
  if (err.code === "ENOENT") {
    console.log("The file you're looking for doesn't exist.");
  }
}

// Operation Timed Out

const request = https.request("https://example.com");

request.on("timeout", () => {
  console.log("The server isn't responding.");
});

request.end();

Potential Applications:

Error handling in web servers and APIs
File system operations
Network communication
Debugging and troubleshooting

Error: TypeError

What is TypeError?

TypeError is an error that occurs when you try to use a value in a way that is not allowed for its type.

Simplified Explanation:

Imagine you have a toy box with different shapes. You have square blocks, circle blocks, and triangle blocks. Each shape has a certain way to fit together. If you try to fit a square block into a circle hole, it won't go. The toy box will say "TypeError" because it expects circle blocks in the circle holes.

Real-World Example:

In real life, type errors can happen when you make a mistake in your code. For example:

let myAge = 25;
myAge = "twenty-five"; // TypeError! Numbers cannot be set to strings.

In this example, the variable myAge is first assigned the number 25. Then, we try to assign the string "twenty-five" to myAge. This causes a TypeError because the myAge variable expects a number, not a string.

Applications in the Real World:

TypeErrors are very useful for catching mistakes in code and preventing unexpected behavior. They help ensure that your code is working as intended and that different parts of your code are using the correct data types.

Here are some examples of applications where TypeErrors can be helpful:

Databases: Ensuring that data is stored in the correct format, such as numbers being stored as numbers and strings being stored as strings.
Website forms: Validating user input to make sure that they enter valid information, such as an email address being an actual email address and a phone number being an actual phone number.
Financial calculations: Making sure that calculations are performed correctly by ensuring that the values used in the calculations are the correct type, such as adding two numbers together instead of adding a number to a string.

Exceptions vs. Errors

Exceptions are like little mistakes that happen when things don't go as planned. They can happen when you do something wrong in your code, like trying to speak a language you don't know.

Errors are a bit more serious. They're like really big mistakes that can crash your whole program. They can happen when something goes wrong with your computer or when you try to do something impossible, like dividing a number by zero.

Node.js Exceptions

Node.js is a popular programming language that makes it easy to build websites and other cool things. It has a special type of exception called an Error object. Error objects have a message that explains what went wrong.

Here's how to throw an exception in Node.js:

throw new Error("This is an exception!");

Unrecoverable Exceptions

Some exceptions are so bad that they can't be fixed by your code. These are called "unrecoverable exceptions." They will always crash your Node.js program.

Real-World Examples

Here are some real-world examples of exceptions and errors:

Exception: Trying to open a file that doesn't exist.
Error: Trying to divide a number by zero.
Unrecoverable Exception: Crashing the computer by using too much memory.

Potential Applications

Exceptions and errors can be useful in a variety of situations:

Catching exceptions: You can use try/catch statements to catch exceptions and handle them gracefully.
Error handling: Errors can be used to report problems and provide feedback to users.
Debugging: Exceptions can help you find bugs in your code.

Simplified Explanation:

OpenSSL Errors

When problems occur while using the crypto or tls modules in Node.js, errors can be triggered. These errors are of the Error class and have additional properties specific to OpenSSL.

Additional OpenSSL-Specific Properties:

1. .code:

A code that identifies the type of error.

2. .message:

A human-readable description of the error.

3. .library:

The OpenSSL library where the error occurred.

4. .reason:

The specific reason for the error.

Real-World Example:

Let's say you're trying to establish a secure connection using TLS and encounter an error. Here's how you can access the additional OpenSSL-specific properties:

try {
  // Code to establish TLS connection
} catch (err) {
  if (err instanceof Error) {
    console.log("OpenSSL Error:");
    console.log("Code:", err.code);
    console.log("Message:", err.message);
    console.log("Library:", err.library);
    console.log("Reason:", err.reason);
  }
}

Potential Applications:

Debugging: Analyzing the error properties can help identify the root cause of the problem and find a solution.
Error Handling: Based on the error code and reason, you can take appropriate actions, such as retrying the operation or displaying a specific error message to the user.
Security Auditing: By checking the error properties, you can verify that the TLS connection is secure and that there are no potential vulnerabilities.

`error.opensslErrorStack`

Simplified Explanation:

error.opensslErrorStack is like a list of clues that helps us understand where an error in the OpenSSL library (which helps with secure communication) came from. It's like a detective tracking down a criminal using footprints and clues.

Detailed Explanation:

What is OpenSSL? OpenSSL is a library that helps with secure communication, like encrypting data so it can't be read by others.
What is an error stack? An error stack is a list of errors that occurred one after the other. It's like a trail of bread crumbs that leads to the original error.
error.opensslErrorStack: This property of an error object contains an array of error clues that give context to the original error. These clues can help developers understand where the error came from in the OpenSSL library.

Example:

Imagine a website that uses SSL (a secure connection) to protect user data. If there's an error with the SSL connection, the error.opensslErrorStack property might contain the following clues:

[
  {
    library: 'ssl',
    function: 'SSL_CTX_load_verify_locations',
    reason: 'file not found'
  },
  {
    library: 'err',
    function: 'ERR_load_crypto_strings',
    reason: 'initialization failure'
  }
]

Real-World Applications:

Debugging: Developers can use error.opensslErrorStack to pinpoint the exact source of an error in the OpenSSL library.
Security: Understanding the context of an error can help identify security vulnerabilities and prevent attacks.
Performance: If there are multiple errors in the stack, developers can optimize performance by addressing the root cause of the first error.

error.function

What is it?
- The name of the OpenSSL function that caused the error.
Simplified Explanation:
- Imagine you're playing a game and you make a mistake. The function name tells you which part of the game you messed up in.

Improved Code Snippet:

try {
  // Some OpenSSL code
} catch (err) {
  console.log(`Error function: ${err.function}`);
}

Real World Application:
- Debugging OpenSSL errors.

error.library

Simplified Explanation:
- This tells you which part of the OpenSSL library caused the error. Imagine OpenSSL as a big castle, with different rooms for different tasks. The error.library tells you which room in the castle the error happened in.
Technical Definition:
- The OpenSSL library the error originates in.

Code Snippet:

const error = new Error("An error occurred");
error.library = "crypto"; // This indicates the error came from the crypto part of OpenSSL

Real-World Implementation:
- Suppose you're using OpenSSL to encrypt and decrypt messages. If an error occurs, error.library can help you identify which part of the encryption or decryption process is causing the issue.
Potential Applications:
- Debugging and troubleshooting OpenSSL-related errors.
- Identifying specific vulnerabilities or issues in the OpenSSL library.
- Providing more detailed error messages to users.

Simplified Explanation of error.reason:

What is error.reason?

Imagine your computer as a big machine with many moving parts. Sometimes, the machine doesn't work as expected and we get an error message. error.reason is like a note that tells us a little bit more about what went wrong.

How to understand it:

The error.reason message is written in plain English, so it's easy to understand. It usually explains what caused the error and what you can do to fix it.

Example:

Let's say you're trying to open a file on your computer, but you accidentally typed the wrong name. You might get an error message like this:

Error: File not found (reason: No such file or directory)

The error.reason message in this case is "No such file or directory." It tells us that the computer cannot find the file because it doesn't exist or is in the wrong location.

Real-World Applications:

Debugging: error.reason can help developers identify the root cause of an error and fix it quickly.
User Assistance: Error messages with clear error.reason messages can help users understand why something went wrong and how to resolve it.
Error Logging: error.reason messages can be logged in a system to provide a detailed record of errors for future analysis.

Complete Code Example:

try {
  // Open a file with the wrong name
  fs.readFile("non-existent-file.txt", (err) => {
    if (err) {
      console.error(err.message); // Output: Error: File not found (reason: No such file or directory)
      console.error(err.reason); // Output: No such file or directory
    }
  });
} catch (err) {
  // Handle the error
}

Potential Applications in the Real World:

E-commerce Websites: Displaying clear error messages with error.reason when users encounter checkout issues.
Web Browsers: Providing detailed error messages to help users resolve connection or website load issues.
Mobile Apps: Showing user-friendly error messages when apps crash or encounter network errors.

Node.js Error Codes

Error codes are numbers that are used to identify different types of errors that can occur in Node.js. They are typically used by the operating system to indicate the cause of an error, but can also be used by Node.js itself to provide more detailed information about an error.

The following are some of the most common error codes in Node.js:

ABORT_ERR: This error code indicates that a process has been aborted.
ENOENT: This error code indicates that a file or directory does not exist.
EACCES: This error code indicates that the user does not have permission to access a file or directory.
EAGAIN: This error code indicates that an operation cannot be completed because the system is temporarily unavailable.
ECONNREFUSED: This error code indicates that a connection was refused.
ETIMEDOUT: This error code indicates that an operation timed out.

These are just a few of the most common error codes in Node.js. For a complete list of error codes, please refer to the Node.js documentation.

Real-World Examples

The following are some real-world examples of how error codes can be used:

A web server can use error codes to indicate the cause of an error to a user. For example, a 404 error code indicates that the requested page does not exist.
A database can use error codes to indicate the cause of an error to a developer. For example, a 1062 error code indicates that a duplicate key was inserted.
A file system can use error codes to indicate the cause of an error to a user. For example, a ENOENT error code indicates that a file does not exist.

Potential Applications

Error codes can be used in a variety of applications, including:

Debugging: Error codes can be used to help identify the cause of an error.
Error handling: Error codes can be used to handle errors in a specific way.
Logging: Error codes can be logged to help track errors.

Conclusion

Error codes are a valuable tool for identifying and handling errors in Node.js. By understanding the different types of error codes, developers can better debug and handle errors in their applications.

ABORT_ERR

Imagine you're playing a board game and you want to stop in the middle. You might say, "Abort!" and throw the pieces back in the box.

In Node.js, ABORT_ERR is like that. It means an operation was stopped before it could finish.

Example:

const controller = new AbortController();

const doSomethingAsync = async () => {
  // Do something that takes a long time
  try {
    const result = await doSomethingAsync();
    // Do something with the result
  } catch (err) {
    if (err.code === "ABORT_ERR") {
      // The operation was aborted
    }
  }
};

controller.abort();

Real-World Application:

You could use ABORT_ERR to stop a file download if the user clicks a "Cancel" button.

Error: Access Denied (ERR_ACCESS_DENIED)

Imagine you have a toy box in your friend's house. You want to play with a toy, but your friend's parents say, "No, you can't touch that toy." This is like the ERR_ACCESS_DENIED error in Node.js.

Node.js tries to do something, like read a file, but it doesn't have permission to do so. It's like trying to play with a toy that you're not supposed to touch.

// Example: Trying to read a file that we don't have permission to read
fs.readFile("secret.txt", (err, data) => {
  if (err) {
    // Oh no! We don't have permission to read this file.
    console.error(err); // Outputs: "Error: Access denied"
  }
});

Applications in the Real World:

Protecting sensitive files from unauthorized access
Preventing users from accessing restricted websites
Enforcing file permissions in collaborative environments (e.g., shared drives)

Error: Ambiguous Argument (ERR_AMBIGUOUS_ARGUMENT)

Imagine you have a function that takes in two arguments: a number and a message. When you call this function, you pass in a number and a message that matches an error message.

The function throws an error because it's confused. It thinks you're trying to specify the expected error message, but you're actually trying to pass in a number.

Simplified Example:

function doSomething(num, message) {
  // ...
}

try {
  doSomething(123, "Error: Something went wrong");
} catch (err) {
  // This will catch the error and print "ERR_AMBIGUOUS_ARGUMENT"
  console.error(err.name);
}

Potential Applications:

This error can help you catch mistakes when you're using functions that take in multiple arguments. It makes sure that you're using the function correctly and prevents unexpected errors from happening.

Simplified Explanation of ERR_ARG_NOT_ITERABLE

"Iterables" are special objects that you can use with for...of loops in JavaScript. They allow you to easily loop through each item in an object.

For example, this code uses a for...of loop to iterate through an array of numbers:

const numbers = [1, 2, 3, 4, 5];

for (const number of numbers) {
  console.log(number); // Logs each number in the array
}

The ERR_ARG_NOT_ITERABLE error occurs when you try to use a for...of loop with something that is not an iterable. For example, the following code will throw this error because 5 is not an iterable:

for (const number of 5) {
  console.log(number);
}

Real-World Applications

Iterables are used in many different places in JavaScript, including:

Looping through arrays
Looping through objects
Creating generators
Using async iterators for asynchronous operations

Potential Applications

Creating custom iterables for your own data structures
Iterating through large datasets efficiently
Creating lazy iterators that only generate values as needed

`ERR_ASSERTION`

Simplified Explanation:

Imagine Node.js as a building. ERR_ASSERTION is like a construction worker who checks for mistakes or broken parts in the building. If the worker finds a problem that should never have happened, like a missing wall or a wonky doorframe, they will raise an ERR_ASSERTION error to say, "Hey, this is not right!"

Real-World Example:

Let's say you're building a website. You have a function that loads data from a database. The data should always be a list, but if something goes wrong, it might be empty. To make sure the data is always a list, you can use the assert module to check it.

const assert = require("assert");

async function getDataFromDatabase() {
  // Load data from database...

  assert.ok(data instanceof Array, "Data must be an array");
}

If the data is not an array, the assert.ok() function will trigger an ERR_ASSERTION error and the website will not load.

Potential Applications:

ERR_ASSERTION errors are used to:

Check for incorrect or unexpected values in functions
Verify that certain conditions are met before continuing execution
Prevent further errors from occurring by catching logic violations early on

`ERR_ASYNC_CALLBACK`

Imagine you have a magic box that can do things for you. To make it work, you need to tell it what to do. You can give it a list of instructions, but each instruction must be a real thing that the box can understand.

Now, let's say you want to tell the box to "jump up and down." This is a clear instruction that the box can follow. But what if you gave it a different instruction, like "make a sandwich"? That wouldn't work because the box doesn't know how to make sandwiches.

The ERR_ASYNC_CALLBACK error is like that. It means you tried to give the magic box an instruction that it couldn't understand. In this case, you tried to give it something that wasn't a real instruction, like a number or a name.

Real-world Example

Imagine you have a robot that can do tasks for you. To make it work, you need to give it a list of commands.

One day, you want the robot to "walk forward." You give it the command "walk forward 10 steps." The robot understands this command and walks forward 10 steps.

But then, you try to give it a different command, like "make a sandwich." The robot doesn't understand this command because it doesn't know how to make sandwiches. It gives you an error message saying "Sorry, I don't know how to do that."

Potential Applications

The ERR_ASYNC_CALLBACK error can be used in many different applications, such as:

Web development: To ensure that only valid functions are used as callbacks in asynchronous operations.
Software testing: To check that callbacks are properly registered and handled.
Error handling: To provide more specific error messages when invalid callbacks are used.

`ERR_ASYNC_TYPE`

This error occurs when you try to use an asynchronous resource (like a file or network request) in a way that's not supported. For example, if you try to read a file synchronously (without waiting for it to finish loading), you'll get this error.

Example:

const fs = require('fs');

try {
  const data = fs.readFileSync('myfile.txt');
} catch (err) {
  // Handle the error
  console.error(err);
}

In this example, we're trying to read the file myfile.txt synchronously using the fs.readFileSync function. This will throw an ERR_ASYNC_TYPE error because fs.readFileSync is a synchronous function and can't be used with asynchronous resources.

Real-world applications

This error can occur in a variety of real-world applications, including:

When you try to use a file or network request in a way that's not supported.
When you try to use an asynchronous resource synchronously.
When you try to use an asynchronous resource in a context where it's not supported.

Potential applications

This error can be used to help you debug your code and identify potential problems with your asynchronous resources.

`ERR_BROTLI_COMPRESSION_FAILED`

Plain English Explanation:

When you try to use the Brotli compression tool to make a file smaller, the compression tool might not work well. This error means that the compression tool couldn't do its job.

Detailed Explanation:

The ERR_BROTLI_COMPRESSION_FAILED error occurs when you use the brotli module to compress data, but the compression fails. This can happen for a few reasons, such as:

The data you're trying to compress is too large.
The data you're trying to compress is already compressed.
The data you're trying to compress contains invalid characters.

Real-World Implementation:

Here's an example of how this error could be thrown in code:

const brotli = require("brotli");

brotli.compress("This is a test string", (err, compressedData) => {
  if (err) {
    // Handle the `ERR_BROTLI_COMPRESSION_FAILED` error
    console.error(err);
  } else {
    // Do something with the compressed data
    console.log(compressedData);
  }
});

In this example, if the data compression fails, the error will be logged to the console.

Potential Applications:

The brotli module can be used to compress a variety of data formats, such as:

Text files
Images
Audio files
Video files

Compressing data can be useful for reducing the size of files, which can be helpful for:

Saving storage space
Reducing bandwidth usage
Improving website performance

ERR_BROTLI_INVALID_PARAM

Explanation: When you try to create a new Brotli stream, which is used for data compression, you might pass in some settings or options. If you mistakenly use an invalid key (like a typo), you'll get this error.

Simplified explanation: Imagine you're building a puzzle, and each piece has a specific place and shape. If you try to fit a piece in the wrong spot or with the wrong shape, the puzzle won't work. Similarly, in the Brotli stream, you need to use the correct settings and options, or the compression process will fail.

Example:

const brotli = require('brotli');

try {
  const stream = brotli.createBrotliStream({'invalid-key': 'value'}); // Invalid key
} catch (err) {
  console.log(err.message); // ERR_BROTLI_INVALID_PARAM
}

Potential applications:

This error can occur in any application that uses Brotli compression, such as web servers or data transfer tools. By understanding the error, developers can ensure that they use the correct settings and avoid data compression issues.

Simplified Explanation

ERR_BUFFER_CONTEXT_NOT_AVAILABLE

Imagine your computer has different "rooms" called JavaScript Engine Contexts. Each room is like a separate playground where you can create things using JavaScript.

Now, let's say you have a Node.js playground in one room and you want to create a special object called a "Buffer" inside another room that doesn't have Node.js.

But wait! That's like trying to build a house in a room that doesn't have any tools. The data you give to build the Buffer will disappear before you even finish making it.

So, instead of trying to build a Buffer in the wrong room, you can create something similar called a "Uint8Array" in the other room. It's like a different kind of house that can do similar things, and it's always available in all rooms.

Real-World Code Example

// Example 1: Node.js Playground
const nodejsBuffer = Buffer.from("Hello Node.js!");
console.log(nodejsBuffer); // Output: <Buffer 48 65 6c 6c 6f 20 4e 6f 64 65 2e 6a 73 21>

// Example 2: JavaScript Engine Context without Node.js
const nonNodejsArray = new Uint8Array([
  72, 101, 108, 108, 111, 32, 110, 111, 110, 101, 106, 115,
]);
console.log(nonNodejsArray); // Output: Uint8Array [72, 101, 108, 108, 111, 32, 110, 111, 110, 101, 106, 115]

Potential Applications

Data Manipulation and Processing: Buffers and Uint8Arrays can be used to manipulate and process binary data.
Image and Audio Processing: They can be used to store and process image and audio data.
Data Encryption and Decryption: Encryption and decryption algorithms can use Buffers and Uint8Arrays to protect sensitive data.
Network Communication: They can be used to send and receive data over networks, such as through HTTP requests and responses.

What is ERR_BUFFER_OUT_OF_BOUNDS?

Imagine a box filled with toys. The box has a certain size, and you can only fit a certain number of toys inside it. If you try to put too many toys in the box, they won't all fit, and some will fall out.

The same thing can happen with Buffer objects in Node.js. A Buffer is like a box that stores data, and it has a certain maximum size. If you try to store more data in a Buffer than it can hold, you'll get the ERR_BUFFER_OUT_OF_BOUNDS error.

How to avoid ERR_BUFFER_OUT_OF_BOUNDS

To avoid getting this error, you need to make sure that you don't try to store more data in a Buffer than it can hold. You can check the size of a Buffer using the length property.

const buffer = Buffer.alloc(10);
console.log(buffer.length); // 10

If you need to store more data than a Buffer can hold, you can create multiple Buffer objects and concatenate them together.

const buffer1 = Buffer.alloc(10);
const buffer2 = Buffer.alloc(10);
const buffer3 = Buffer.concat([buffer1, buffer2]);
console.log(buffer3.length); // 20

Real-world applications

Buffer objects are used in Node.js to handle binary data. This data can come from a variety of sources, such as files, network connections, or databases.

Some examples of real-world applications where you might use Buffer objects include:

Reading and writing files
Sending and receiving data over a network
Storing binary data in a database
Processing images or other binary data

`ERR_BUFFER_TOO_LARGE`

Simplified Explanation:

Pretend you have a big box to fill with toys. But the box has a limit to how many toys it can hold. If you try to put too many toys in it, the box will overflow and you won't be able to fit them all.

Detailed Explanation:

In Node.js, a Buffer is like a box that stores data. Just like a real box has a maximum size, a Buffer has a maximum amount of data it can hold.

The ERR_BUFFER_TOO_LARGE error occurs when you try to create a Buffer that's larger than the maximum allowed size. This is like trying to put too many toys in a box that's too small.

Code Snippet:

// Creating a Buffer larger than the maximum allowed size
const tooLargeBuffer = Buffer.alloc(1000000000);

// Throws ERR_BUFFER_TOO_LARGE error

Potential Applications in Real World:

File Transfer: When transferring large files, it's important to check if the file size exceeds the maximum allowed buffer size to avoid errors.
Image Processing: When working with large images, it's crucial to ensure that the image data doesn't exceed the buffer size limit to prevent crashes or data loss.
Streaming Data: In real-time applications that handle large data streams, it's important to monitor the buffer size to prevent overflows and data loss.

ERR_CANNOT_WATCH_SIGINT

The operating system did not allow Node.js to watch for the SIGINT signal (also known as Control-C). This can happen when Node.js is running in a restricted environment, such as a container or a sandbox.
Simplified explanation: Node.js wasn't able to listen for when you press Control-C.

Real-world example:

$ node
> process.kill(process.pid, 'SIGINT');
ERR_CANNOT_WATCH_SIGINT: Cannot watch for SIGINT signal

Potential applications:

Controlling Node.js processes remotely (e.g., via SSH)
Gracefully shutting down Node.js applications when the user presses Control-C

`ERR_CHILD_CLOSED_BEFORE_REPLY`

What is it?

This error occurs when a child process is closed before the parent process receives a reply from it.

How to fix it?

Make sure the child process does not close before the parent process is ready to receive its reply.

Example:

const { fork } = require("child_process");

const child = fork("child.js");

child.on("message", (message) => {
  // Do something with the message
});

child.send("Hello");

child.once("close", () => {
  // The child process has closed.
  // Do something...
});

In this example, the parent process forks a child process and sends it a message. The parent process then listens for messages from the child process and when it receives one, it does something with it. The parent process also listens for the child process to close and when it does, it does something else.

Real-world applications:

Communicating between different processes in a distributed system
Running long-running tasks in the background

`ERR_CHILD_PROCESS_IPC_REQUIRED`

When you want to create a new process (child process) from an existing process (parent process), you need to establish a way for the two processes to communicate with each other. This is called IPC (Inter-Process Communication).

When you create a child process using child_process.fork(), you need to specify how the parent and child processes will communicate. You can do this by passing an IPC channel to the fork() function.

If you don't specify an IPC channel, Node.js will throw an ERR_CHILD_PROCESS_IPC_REQUIRED error.

const childProcess = require("child_process");

// Create a child process without specifying an IPC channel
const child = childProcess.fork("child.js");

// This will throw an ERR_CHILD_PROCESS_IPC_REQUIRED error
child.send("Hello from parent");

To fix this error, you need to specify an IPC channel when you create the child process.

const childProcess = require("child_process");

// Create a child process with an IPC channel
const child = childProcess.fork("child.js", {
  stdio: ["pipe", "pipe", "pipe", "ipc"],
});

// Now you can send messages to the child process using the IPC channel
child.send("Hello from parent");

Real-world applications

IPC is used in a variety of real-world applications, including:

Message passing: Child processes can send messages to their parent process, and vice versa. This can be used for a variety of purposes, such as logging, error reporting, and progress updates.
Data sharing: Child processes can share data with their parent process, and vice versa. This can be used for a variety of purposes, such as sharing configuration data or the results of a computation.
Process control: Parent processes can control their child processes, such as starting, stopping, or killing them. This can be used for a variety of purposes, such as managing resources or responding to user input.

Simplified Explanation:

ERR_CHILD_PROCESS_STDIO_MAXBUFFER occurs when you try to read too much data from a child process's standard output or standard error.

Topic: Child Process

A child process is a new process that you create from the original process. It's like a little helper that can do tasks for the original process.

Topic: STDERR/STDOUT

Every process has two special channels called standard error (STDERR) and standard output (STDOUT). Processes can write error messages to STDERR and data to STDOUT.

Topic: Max Buffer

When you read data from a process, it's stored in a buffer. If the buffer gets too big, it can cause an error. The maxBuffer option controls how big the buffer can get before it causes an error.

Real-World Example:

Imagine you're running a command that generates a lot of output. You try to read the output, but it's so big that it fills up the buffer and causes an error.

Potential Application:

You could use this error to detect processes that are generating too much output and take appropriate action, such as killing the process or increasing the maxBuffer option.

Code Snippet:

const { exec } = require('child_process');

// Create a child process
const child = exec('ls -l', (err, stdout, stderr) => {
  // Read the output
  console.log(stdout);

  // Handle the error
  if (err) {
    if (err.code === 'ERR_CHILD_PROCESS_STDIO_MAXBUFFER') {
      // The buffer got too big
      console.error('The output was too large.');
    } else {
      // Other error occurred
      console.error(err);
    }
  }
});

// Increase the max buffer size to prevent the error
child.stdout.setMaxListeners(0);

`ERR_CLOSED_MESSAGE_PORT`

Simplified Explanation:

Imagine you have a pipe or hose with two ends. Each end is like a "message port" that allows you to send messages.

If you close one end of the pipe, you can't send messages through it anymore. That's what happens with ERR_CLOSED_MESSAGE_PORT.

Technical Details:

ERR_CLOSED_MESSAGE_PORT is an error that happens when you try to use a MessagePort object that has been closed. MessagePort objects are used to send messages between different parts of your code.

Real-World Example:

Imagine you have a website with a chat feature. When someone sends a message, you create a MessagePort object to send the message to the recipient. If the recipient closes their web browser before receiving the message, you'll get ERR_CLOSED_MESSAGE_PORT.

Complete Code Implementation:

const { MessagePort } = require("worker_threads");

const port1 = new MessagePort();
const port2 = new MessagePort();

port1.postMessage("Hello from port 1"); // Sends a message

port2.close(); // Closes port 2

try {
  port2.postMessage("Hello from port 2"); // Will throw ERR_CLOSED_MESSAGE_PORT
} catch (err) {
  console.error(err); // Outputs: Error: MessagePort closed
}

Potential Applications:

MessagePort objects are typically used in web development for communication between different parts of a web application, such as the main page and a worker thread. They can also be used to communicate between different Node.js processes.

ERR_CONSOLE_WRITABLE_STREAM

Simplified Explanation: The error occurs when you try to use the Console object to write to the standard output (stdout) or standard error (stderr) streams, but these streams are not available or are not writable. The Console object needs writeable streams to work properly.

Detailed Explanation: The Console object in Node.js is a global object used to write messages to the command line or terminal window. It has two main streams:

stdout: Used for writing normal messages.
stderr: Used for writing error messages or warnings.

These streams must be writable to function correctly. If the streams are not writable or are unavailable, the ERR_CONSOLE_WRITABLE_STREAM error is thrown.

Code Snippet:

// Create a console object without specifying stdout stream
const consoleWithoutStdout = new console.Console();

// Attempt to write to stdout, resulting in the error
consoleWithoutStdout.log("Hello World!");

Real-World Applications: The ERR_CONSOLE_WRITABLE_STREAM error can occur in various scenarios:

When writing to the console is disabled, such as when running in a headless environment (e.g., a server without a display).
When the streams are redirected to files or other destinations, making them non-writable.
When using custom console implementations that do not provide writable streams.

Potential Solutions: To resolve the error, you need to ensure that the stdout and stderr streams are writable. Here are some possible solutions:

Check the environment and make sure that terminal output is enabled.
Redirect the streams to writable destinations, such as files or network sockets.
Use a custom console implementation that provides writable streams.

`ERR_CONSTRUCT_CALL_INVALID`

Simplified Explanation:

You tried to call a function that is not supposed to be called like a constructor (like you would with new).

In-depth Explanation:

In JavaScript, constructors are special functions that are used to create new objects. They are called with the new keyword. However, some functions are not meant to be called as constructors. For example, regular functions or arrow functions cannot be called with new.

If you try to call a function that is not a constructor with new, you will get the ERR_CONSTRUCT_CALL_INVALID error.

Code Snippet:

// This will throw ERR_CONSTRUCT_CALL_INVALID
function NotAConstructor() {}

const instance = new NotAConstructor(); // Error: ERR_CONSTRUCT_CALL_INVALID

Real-World Application:

This error is useful for preventing accidental misuse of functions. For example, if you have a function that is meant to be used as a normal function, but you accidentally call it with new, you will get this error and you will know that you are using it incorrectly.

`ERR_CONSTRUCT_CALL_REQUIRED`

Simplified Explanation:

You forgot to use the new keyword when you called a class constructor.

Detailed Explanation:

In JavaScript, classes are blueprints for creating objects. A constructor is a special function that's called when you create a new object from a class.

To create an object from a class, you need to use the new keyword before the class name. For example:

class MyClass {
  // Constructor
  constructor() {
    // Code to initialize the object
  }
}

// Create a new object from the class
const myObject = new MyClass();

If you forget to use the new keyword, you'll get the ERR_CONSTRUCT_CALL_REQUIRED error.

Code Snippet:

The following code will throw the ERR_CONSTRUCT_CALL_REQUIRED error:

class MyClass {
  // Constructor
  constructor() {
    // Code to initialize the object
  }
}

// Create an object from the class without using 'new'
const myObject = MyClass(); // Error: ERR_CONSTRUCT_CALL_REQUIRED

Real-World Example:

Let's say you have a class called Person that represents a person. The constructor of the Person class initializes the person's name and age.

If you try to create a Person object without using the new keyword, you'll get the ERR_CONSTRUCT_CALL_REQUIRED error.

Potential Applications:

The ERR_CONSTRUCT_CALL_REQUIRED error helps you ensure that objects are created properly from classes. This error prevents you from creating objects that may be incomplete or have incorrect properties.

ERR_CONTEXT_NOT_INITIALIZED

This error occurs when you try to use a virtual machine (VM) context before it has been initialized.

Simplified Explanation for a Child:

Imagine you have a new toy that needs batteries before you can play with it. If you try to use the toy without putting in the batteries, it won't work. The same thing happens with a VM context - you need to initialize it before you can use it.

Code Snippet:

try {
  // Create a VM context
  const context = new vm.Context();
} catch (err) {
  if (err.code === "ERR_CONTEXT_NOT_INITIALIZED") {
    // Handle the error
  }
}

Real-World Applications:

VM contexts are used to create isolated environments for running code. This can be useful for security, testing, or running different versions of a program.

Potential Applications:

Sandboxing untrusted code to prevent malicious activity
Testing code changes in isolation without affecting the main program
Running legacy code on modern operating systems

`ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED`

Simplified Explanation:

OpenSSL engines are like different tools that you can use to perform encryption tasks. Imagine you're building a house, and you need to hammer some nails. You can use a regular hammer or a special hammer designed for construction.

In Node.js, you can specify which OpenSSL engine to use when you're making secure connections. But sometimes, the engine you want to use might not be available because it's not supported by the version of OpenSSL that's being used.

It's like trying to use a special construction hammer with a regular toolbox. The toolbox doesn't have the right slot for that hammer, so you can't use it.

Real-World Example:

Here's a simplified example:

// Using a special OpenSSL engine
const tlsOptions = {
  clientCertEngine: "mySpecialEngine",
};

// Create a secure connection
const socket = tls.connect(tlsOptions);

// The connection fails with the following error:
// Error: ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED

In this example, the clientCertEngine option specifies a special OpenSSL engine. However, the version of OpenSSL being used doesn't support that engine, so the connection fails with the error ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED.

Potential Applications:

OpenSSL engines have various applications in the real world, including:

Securely storing and managing cryptographic keys
Encrypting and decrypting data
Performing digital signatures
Generating random numbers

What is ERR_CRYPTO_ECDH_INVALID_FORMAT?

Imagine you're trying to communicate secretly with your best friend using a special code, but you need a way to exchange the secret code safely. That's where ECDH (Elliptic Curve Diffie-Hellman) comes in. It's like a special handshake that lets you securely share a secret code.

But oops! Sometimes, you might use the wrong handshake format, like trying to shake hands with your pinky instead of your thumb. That's when you get the error ERR_CRYPTO_ECDH_INVALID_FORMAT. It means you're using the wrong handshake method.

How to fix it:

Make sure you're using the correct handshake format, which is usually specified by the software or protocol you're using.

Real-world example:

Let's say you want to securely exchange a password with a friend over the internet. You can use ECDH to create a secret code that you can both use to encrypt and decrypt the password.

Code example:

const crypto = require("crypto");

// Create an ECDH key pair for yourself
const privateKey = crypto.createECDH("secp521r1");
const publicKey = privateKey.generateKeys();

// Share your public key with your friend
// ...

// Receive your friend's public key
// ...

// Create a shared secret using your private key and your friend's public key
const secret = privateKey.computeSecret(friendPublicKey);

Applications in the real world:

Securely communicating passwords, messages, and other sensitive data over the internet
Establishing secure connections between devices
Creating digital signatures for verifying the authenticity of documents

Simplified Explanation:

When using the crypto.ECDH() class in Node.js to create a secret, you need to provide a public key. If the public key is not valid (i.e., it is not on the correct elliptic curve), the ERR_CRYPTO_ECDH_INVALID_PUBLIC_KEY error will be thrown.

Detailed Explanation:

Elliptic Curve Diffie-Hellman (ECDH) is a cryptographic algorithm used to securely exchange secrets between two parties. To do this, each party generates a public and private key pair. The public keys are shared between the parties, while the private keys are kept secret.

When you create an ECDH object in Node.js, you need to provide the public key of the other party. This public key is used to compute a shared secret that can be used to encrypt and decrypt messages.

If the public key is invalid, the computeSecret() method will fail and throw the ERR_CRYPTO_ECDH_INVALID_PUBLIC_KEY error. This is because the invalid public key does not lie on the correct elliptic curve, which means that it cannot be used to compute a shared secret.

Code Snippet:

const crypto = require("crypto");

try {
  const ecdh = crypto.createECDH("secp256k1");
  ecdh.generateKeys();

  const otherPublicKey = "invalid public key";
  ecdh.computeSecret(otherPublicKey);
} catch (err) {
  // Handle the error
  if (err.code === "ERR_CRYPTO_ECDH_INVALID_PUBLIC_KEY") {
    // The public key is invalid
  }
}

Real-World Applications:

ECDH is used in a variety of real-world applications, including:

Secure messaging
Key exchange for TLS connections
Authentication and authorization

By using ECDH, you can securely exchange secrets with other parties, even if you are not directly connected to them.

`ERR_CRYPTO_ENGINE_UNKNOWN`

In the Node.js ['crypto'][crypto] module, there's a function called setEngine() that lets you use a specific cryptographic engine for certain operations. But if you try to use an invalid engine identifier with this function, you'll get the ERR_CRYPTO_ENGINE_UNKNOWN error.

Simplified Explanation:

Imagine you want to use a particular tool in your tool kit (the engine) to perform a specific task. If you use a tool that's not in your kit (an invalid engine identifier), you won't be able to do the task and you'll get an error message.

Code Snippet:

const crypto = require("node:crypto");

try {
  // Using an invalid engine identifier
  crypto.setEngine("non-existing-engine");
} catch (err) {
  // Handle the ERR_CRYPTO_ENGINE_UNKNOWN error here
  console.error(err.message);
}

Real-World Application:

Cryptographic engines are used to perform various cryptographic operations, such as encryption and decryption. In real-world applications, you might need to use a specific cryptographic engine that meets certain security or performance requirements. If you try to use an unsupported or invalid engine, you'll encounter this error.

Improved Version:

To avoid this error, make sure you use a valid engine identifier when calling setEngine(). The list of supported engine identifiers can be obtained using crypto.getEngineNames().

const crypto = require("node:crypto");

const engineNames = crypto.getEngineNames();
if (engineNames.includes("my-engine-identifier")) {
  crypto.setEngine("my-engine-identifier");
}

ERR_CRYPTO_FIPS_FORCED

Simplified Explanation:

You tried to change the "FIPS mode" setting in the node:crypto module, but you had already told Node.js to force FIPS mode using the --force-fips command-line argument. When you force FIPS mode, you can't change it again.

Technical Explanation:

FIPS mode stands for "Federal Information Processing Standards" mode. It's a special setting in the node:crypto module that makes sure all cryptographic operations follow strict government standards for security.

The --force-fips command-line argument tells Node.js to always use FIPS mode, even if the code you're running tries to turn it off. This is often used for extra security in applications that handle sensitive data.

Once you've forced FIPS mode, you can't change it back. This is because FIPS mode is designed to be a permanent setting for increased security.

Real-World Example:

A government agency may use Node.js to encrypt and decrypt classified data. They would use the --force-fips argument to ensure that all cryptographic operations meet the strict FIPS standards required for government use.

Simplified Code Snippet:

// Start Node.js with FIPS mode forced
node --force-fips my-app.js

// Attempt to disable FIPS mode (won't work)
const crypto = require('crypto');
crypto.setFips(false);

Potential Applications:

Ensuring compliance with government regulations for secure data handling
Protecting sensitive information in healthcare, finance, and government systems

ERR_CRYPTO_FIPS_UNAVAILABLE

Explanation:

Imagine you have a special mode on your computer called "FIPS mode." This mode makes sure that all the security measures you use are super strong and meet strict government standards.

But sometimes, even if you want to use FIPS mode, your computer might not be allowed to. This can happen if your computer doesn't have the right settings or if it's missing something important.

When this happens, you'll see an error message called "ERR_CRYPTO_FIPS_UNAVAILABLE." It means that FIPS mode is not available on your computer right now.

Real-World Example:

Imagine you're creating a website that needs to be extra secure. You want to make sure that all the passwords and sensitive information you store on the website are protected to the highest level.

You try to enable FIPS mode on your computer, but you get the "ERR_CRYPTO_FIPS_UNAVAILABLE" error. This means that your computer can't use FIPS mode, so you have to find another way to make your website secure.

`ERR_CRYPTO_HASH_FINALIZED`

Simplified Explanation:

When you use the hash.digest() method in Node.js, you're asking the program to calculate a hash value for some data you've given it. This hash value is a unique fingerprint that represents your data, and it's used for things like checking data integrity and creating secure passwords.

The ERR_CRYPTO_HASH_FINALIZED error happens when you try to call the hash.digest() method more than once for the same data. This is a no-no because the hash value has already been calculated and can't be changed.

Real-World Code Implementation:

const crypto = require("crypto");

// Create a hash object
const hash = crypto.createHash("sha256");

// Add some data to the hash
hash.update("Hello, world!");

// Calculate the hash value
const hashValue = hash.digest("hex");

// Try to calculate the hash value again
try {
  hash.digest("hex");
} catch (err) {
  // Error: ERR_CRYPTO_HASH_FINALIZED
}

Potential Applications:

Verifying the integrity of downloaded files
Creating secure passwords
Checking the authenticity of documents

ERR_CRYPTO_HASH_UPDATE_FAILED

This error occurs when the hash.update() method fails to update the hash. This is a rare error that should not happen under normal circumstances.

Real-World Example

const crypto = require("crypto");

const hash = crypto.createHash("sha256");
hash.update("Hello world");
hash.update("!"); // This line will cause the error

// Output:
// Error: ERR_CRYPTO_HASH_UPDATE_FAILED

In this example, we create a hash object using the crypto.createHash() method. We then update the hash using the hash.update() method. However, the second hash.update() call will cause the error because the hash has already been finalized.

Potential Applications

Hashing data for security purposes
Verifying the integrity of data
Creating digital signatures

Simplified Explanation

Imagine you have a special machine that can turn any message into a unique number. This number is called a hash.

The hash.update() method is like adding ingredients to the machine. Each time you add an ingredient, the machine recalculates the hash.

However, if you try to add an ingredient after the machine has already finished calculating the hash, it will break. This is because the machine can only calculate the hash once.

Code Snippet

const crypto = require("crypto");

const hash = crypto.createHash("sha256");
hash.update("Hello world");
const hashedMessage = hash.digest("hex"); // Get the hash as a hexadecimal string

console.log(hashedMessage); // Output: 'b94d27b9934d3e08a52e52d7da7dabfac484efe37a5380ee9088f7ace2efcde9'

In this example, we create a hash object and update it with the message "Hello world". We then use the hash.digest() method to get the final hash as a hexadecimal string.

Real-World Applications

Hashing passwords: When you create a password, it is hashed and stored in the database. This way, if the database is hacked, the passwords cannot be stolen.
Verifying the integrity of files: When you download a file, you can hash it and compare it to the hash of the original file. This way, you can verify that the file has not been tampered with.
Creating digital signatures: A digital signature is a way to prove that a message came from a specific person. This is done by hashing the message and encrypting the hash using the person's private key.

Simplified Explanation of `ERR_CRYPTO_INCOMPATIBLE_KEY` Error

What is this error?

Imagine you have two different types of keys: a door key and a car key. If you try to use the car key to open the door, it won't work because they're not compatible. That's exactly what happens with ERR_CRYPTO_INCOMPATIBLE_KEY.

In Node.js, you use crypto keys to encrypt and decrypt data. For example, if you want to keep a secret message safe, you can encrypt it with a key. To read the message later, you need to use the same key to decrypt it.

But sometimes, you might try to use the wrong key. For example, if you encrypted data with a key from a different encryption algorithm, trying to decrypt it with a key from a different algorithm won't work. That's when you'll get the ERR_CRYPTO_INCOMPATIBLE_KEY error.

How to fix it:

To fix this error, you need to make sure you're using the correct key for the operation you're trying to perform. Check that you're using the same key that was used to encrypt the data.

Real-world example:

Let's say you want to encrypt a message with a particular algorithm called AES-256. Once encrypted, you realize that you accidentally used a different algorithm, RSA-2048, to decrypt it. This will result in the ERR_CRYPTO_INCOMPATIBLE_KEY error. To resolve this, you need to use the correct AES-256 key to decrypt the encrypted data.

Potential applications:

Secure communication (e.g., sending encrypted emails or messages)
Data encryption and decryption (e.g., protecting sensitive information stored on devices or databases)
Digital signatures (e.g., verifying the authenticity of documents or messages)

`ERR_CRYPTO_INCOMPATIBLE_KEY_OPTIONS`

Simplified Explanation:

When using encryption, we need to use the correct settings for the keys we use. If we mix and match settings, we will get this error.

Detailed Explanation:

When encrypting data, we use a public-private key pair. The public key is used to encrypt, and the private key is used to decrypt.

The error ERR_CRYPTO_INCOMPATIBLE_KEY_OPTIONS occurs when we try to use a public key to encrypt data that was encrypted with a private key, or vice versa.

// This will throw an error because we are mixing public and private keys.
const crypto = require("crypto");

const publicKey = crypto.createPublicKey("...");
const privateKey = crypto.createPrivateKey("...");

const encryptedData = crypto.publicEncrypt(
  publicKey,
  Buffer.from("Hello world!")
);

// Attempting to decrypt with the private key will fail.
crypto.privateDecrypt(privateKey, encryptedData); // Error: ERR_CRYPTO_INCOMPATIBLE_KEY_OPTIONS

`ERR_CRYPTO_INITIALIZATION_FAILED`

Simplified Explanation:

When using encryption, we need to set up the encryption correctly. If we don't do this properly, we will get this error.

Detailed Explanation:

To use encryption, we need to initialize the encryption library. If we don't do this properly, we will get the error ERR_CRYPTO_INITIALIZATION_FAILED.

// This will throw an error because we have not initialized the encryption library.
const crypto = require("crypto");

crypto.createCipher("aes-256-cbc", "..."); // Error: ERR_CRYPTO_INITIALIZATION_FAILED

Real-World Applications

Encryption is used in many real-world applications:

Secure communication: Encrypting messages and emails to prevent eavesdropping.
Data storage: Encrypting data at rest to prevent unauthorized access.
Digital signatures: Using public-key encryption to verify the authenticity of digital documents.

Code Implementations

Secure communication using TLS:

const tls = require("tls");

const server = tls.createServer({
  cert: fs.readFileSync("server.crt"),
  key: fs.readFileSync("server.key"),
});

server.listen(443);

Data storage using encryption:

const crypto = require("crypto");

const cipher = crypto.createCipher("aes-256-cbc", "...");

const encryptedData = cipher.update("Hello world!", "utf8");

encryptedData += cipher.final();

Digital signatures using public-key encryption:

const crypto = require("crypto");

const privateKey = crypto.createPrivateKey("...");
const publicKey = crypto.createPublicKey("...");

const signature = crypto.sign(
  "sha256",
  Buffer.from("Hello world!"),
  privateKey
);

const verified = crypto.verify(
  "sha256",
  Buffer.from("Hello world!"),
  publicKey,
  signature
);

ERR_CRYPTO_INITIALIZATION_FAILED: Crypto Subsystem Failed to Initialize

Imagine the crypto subsystem in Node.js as a secret safe. When you start Node.js, we try to unlock this safe. However, if we can't unlock it, you'll see this error.

Potential Reasons:

You might be using an outdated version of Node.js. Update to the latest stable version.
There might be a problem with your system's OpenSSL library. The OpenSSL library helps Node.js handle encryption and decryption. Try updating or reinstalling OpenSSL.

Real-World Applications:

Secure communication like online banking, where encryption is used to protect your financial information.

Code Example:

Suppose you're trying to encrypt a message, but you're getting this error.

const crypto = require('crypto');

const message = 'Hello, world!';

// Attempt to encrypt the message
const encryptedMessage = crypto.createCipher('aes-256-cbc', 'secret key').update(message, 'utf8', 'base64');

// If the crypto subsystem fails to initialize, you'll see this error:
console.log(encryptedMessage); // ERR_CRYPTO_INITIALIZATION_FAILED

In this case, update your version of Node.js or OpenSSL and try again.

ERR_CRYPTO_INVALID_AUTH_TAG

Simplified Explanation:

Imagine you have a secret box. To lock it, you use a key and a special tag that proves the key is the right one. When you open the box, you use the same key and tag to make sure the tag matches. If the tag doesn't match, it means someone has tampered with the box, and you can't be sure what's inside.

ERR_CRYPTO_INVALID_COUNTER

Simplified Explanation:

Imagine you have a list of secret numbers. Each number has a special counter that counts how many times it has been used. When you use a number, you also update its counter. If you try to use a number again with the wrong counter, it means someone has changed the counter, and you can't be sure the number is still valid.

Real-World Applications:

These errors are used in cryptography, which is a way of protecting sensitive information. They help ensure that data is not tampered with or accessed by unauthorized people.

Example:

const crypto = require("crypto");

// Create a secret box
const box = crypto.createCipheriv(
  "aes-256-gcm",
  Buffer.from("my secret key"),
  Buffer.from("my initialization vector")
);

// Encrypt some data
const encryptedData = box.update("Hello, world!", "utf8");

// Add the authentication tag
const tag = box.final("hex");

// Check if the tag is valid
const decryptedData = crypto.createDecipheriv(
  "aes-256-gcm",
  Buffer.from("my secret key"),
  Buffer.from("my initialization vector")
);
decryptedData.setAuthTag(Buffer.from(tag, "hex"));

try {
  // This will fail if the tag is invalid
  decryptedData.update("Hello, world!", "utf8");
} catch (err) {
  console.log("ERR_CRYPTO_INVALID_AUTH_TAG");
}

Simplified Explanation of ERR_CRYPTO_INVALID_COUNTER

What is a counter-mode cipher?

Imagine a secret code where each letter is replaced by a different letter, like this:

A -> B
B -> C
C -> D

In a counter-mode cipher, instead of always using the same code, we use a "counter" to change the code each time we encrypt a message. This makes the code harder to break.

What is an invalid counter?

The "counter" is a number that tells the cipher how to change the code. If we use the wrong counter, the code won't work properly and we won't be able to encrypt or decrypt our message.

Real-World Implementation

Imagine you're sending a secret message to your friend using the counter-mode cipher. If you use the wrong counter, your friend won't be able to read your message.

Potential Applications

Counter-mode ciphers are used in many real-world applications, such as:

Encrypting data in databases
Securing network traffic
Protecting sensitive information from unauthorized access

Simplified Explanation of `ERR_CRYPTO_INVALID_CURVE`

What is a curve? A curve is a mathematical shape like a circle or a line. In this case, it's a special type of curve used in cryptography.

What's wrong with the curve? The curve you gave to the computer is not one of the valid curves that the computer knows about. It's like trying to use a square as a wheel.

Real-World Example

Imagine you're a spy trying to send a secret message to your team. You use a special code to encrypt the message. But if you use the wrong code, the message will be gibberish. The same thing happens here with curves. If you use the wrong curve, the encryption won't work, and the message will be useless.

Potential Applications

Curves are used in various real-world applications, such as:

Secure messaging apps
Online banking
Cryptocurrency transactions

They help keep sensitive information safe by encrypting it and making it difficult for unauthorized people to access.

Simplified Explanation of ERR_CRYPTO_INVALID_DIGEST

What is a Crypto Digest Algorithm?

Imagine you have a long secret message you want to send to someone. You use a secret key to encrypt the message, which turns it into a scrambled code. To make sure the recipient can decrypt the message correctly, you also create a "digest" of the original message using a special function called a digest algorithm. The digest is a short, unique code that represents the original message.

What is ERR_CRYPTO_INVALID_DIGEST?

This error occurs when you try to use an invalid digest algorithm. It's like using the wrong key to unlock a door. The key may look similar, but it won't work because it's not the right one for that particular door.

Real-World Example

Let's say you want to send a secret email to your friend using your favorite encryption software. When you select the digest algorithm, you accidentally choose "MD5" instead of "SHA-256." Oops! The encryption software will give you this error because MD5 is not a valid algorithm for that software.

Potential Applications

Crypto digest algorithms are used in many real-world applications, including:

Secure messaging: To verify the integrity of encrypted messages
Digital signatures: To ensure that a document has not been tampered with
Blockchain technology: To create unique identifiers for transactions

Simplified Explanation of ERR_CRYPTO_INVALID_IV:

Imagine you're sending a secret message to your friend. To make sure it doesn't get intercepted, you use a special code called a "initialization vector" or "IV" to shuffle the message. However, if the IV you enter is not correct, the message will become scrambled and your friend won't be able to read it. That's when you get the error ERR_CRYPTO_INVALID_IV.

Real-World Example:

Let's say you're building an app to securely send messages between users. The app uses an encryption technique that requires an IV to scramble the messages. If a user accidentally enters the wrong IV when sending a message, they will receive the ERR_CRYPTO_INVALID_IV error, and the message will remain unsent.

Potential Applications:

Secure communication in messaging apps
Encryption in cloud storage systems
Protection of sensitive data in databases
Authentication and authorization in blockchain networks

Simplified Explanation:

An ERR_CRYPTO_INVALID_JWK error means you gave the computer a key that it didn't understand. It's like giving your car a key to a different car. The car won't start because it doesn't know what to do with the key.

Topics in Detail:

JSON Web Key (JWK): A JWK is a special type of key used in cryptography, which is the way computers keep things secret. A JWK looks like a JSON object, which is a way of writing data in a structured format.
Invalid JWK: A JWK is invalid if it's missing required information, contains incorrect data, or is in the wrong format.

Code Implementations:

// Example 1: Trying to use an invalid JWK
const invalidJWK = {};  // This JWK is missing required information

try {
  // Attempt to use the invalid JWK
  crypto.verify(..., { key: invalidJWK });
} catch (err) {
  // An ERR_CRYPTO_INVALID_JWK error will be thrown here
  console.error(err);
}

// Example 2: Using a valid JWK
const validJWK = {
  kty: "RSA",
  n: "...",  // Public key modulus
  e: "...",  // Public key exponent
};

crypto.verify(..., { key: validJWK });  // No error is thrown

Real-World Applications:

Secure communication: JWKs are used in various protocols, such as JSON Web Tokens (JWTs), to establish secure communication between applications.
Encryption and decryption: JWKs can be used to encrypt and decrypt sensitive data, ensuring its confidentiality and integrity.

Potential Improvements:

Better error message: The error message could be improved to provide more specific information about the invalidity of the JWK.
Automatic JWK validation: Some libraries could provide automatic validation of JWKs to prevent invalid keys from being used.

ERR_CRYPTO_INVALID_KEY_OBJECT_TYPE

What is it?

This error occurs when you try to use a crypto key object that has the wrong type for the operation you're trying to perform.

Example:

Imagine you have a key that is used for encrypting data. You can't use this key to decrypt data because encryption and decryption require different types of keys.

How to fix it:

Make sure you're using the correct type of key for the operation you're trying to perform.

Code Example:

This code will generate a key for encrypting data:

const crypto = require('crypto');
const key = crypto.createCipheriv('aes-256-cbc', 'mypassword');

This code will generate a key for decrypting data:

const crypto = require('crypto');
const key = crypto.createDecipheriv('aes-256-cbc', 'mypassword');

Real-world applications:

Crypto keys are used in a variety of real-world applications, such as:

Encrypting data at rest (e.g., storing sensitive information in a database)
Encrypting data in transit (e.g., sending sensitive information over a network)
Verifying the authenticity of data (e.g., ensuring that a message has not been tampered with)

Explanation:

ERR_CRYPTO_INVALID_KEYLEN

What it is: This error occurs when you try to create a cryptographic key with an invalid length.
Why it happens: The length of the key is too short or too long according to the algorithm being used.
How to fix it: Use a valid key length for the algorithm you're using.

ERR_CRYPTO_INVALID_KEYPAIR

What it is: This error occurs when you try to use an invalid key pair for encryption or decryption.
Why it happens: The key pair is not properly matched or is corrupted.
How to fix it: Generate a new key pair or verify that the existing key pair is correct.

Code Implementations:

// Invalid Key Length
const crypto = require("crypto");

try {
  // Attempt to create a 128-bit key (valid length for AES algorithm)
  const key = crypto.randomBytes(128);

  // Attempt to create a 256-bit key (invalid length for AES algorithm)
  const key2 = crypto.randomBytes(256);
} catch (err) {
  if (err.code === "ERR_CRYPTO_INVALID_KEYLEN") {
    console.log("Invalid key length:", err.message);
  } else {
    throw err;
  }
}

// Invalid Key Pair
const crypto = require("crypto");

try {
  const { publicKey, privateKey } = crypto.generateKeyPairSync("rsa", {
    modulusLength: 2048,
  });

  // Encrypt data using the private key
  const encryptedData = crypto.privateEncrypt(
    privateKey,
    Buffer.from("secret")
  );

  // Attempt to decrypt the data using the public key (invalid key pair)
  const decryptedData = crypto.publicDecrypt(publicKey, encryptedData);
} catch (err) {
  if (err.code === "ERR_CRYPTO_INVALID_KEYPAIR") {
    console.log("Invalid key pair:", err.message);
  } else {
    throw err;
  }
}

Applications in Real World:

Secure communication: Encryption and decryption using valid key lengths and key pairs is crucial for protecting sensitive data in online communication.
Digital signatures: Creating and verifying digital signatures requires valid key pairs to ensure authenticity and integrity of data.
Data storage: Encrypting data on disk or in the cloud requires using valid key lengths and key pairs to protect it from unauthorized access.

`ERR_CRYPTO_INVALID_KEYPAIR`

Simplified Explanation: Your key is broken, so you can't use it to encrypt or decrypt data.

Real World Analogy: Imagine your house key. If it's broken or the wrong one, you won't be able to unlock your door.

`ERR_CRYPTO_INVALID_KEYTYPE`

Simplified Explanation: You're trying to use the wrong type of key for the encryption or decryption process.

Real World Analogy: Think of a padlock and a key. If you have a padlock that's only compatible with a certain type of key, you can't use any other key to unlock it.

Code Implementation:

// Attempt to encrypt data with an invalid key pair
const crypto = require("crypto");

const keyPair = {
  publicKey: "invalid_key",
  privateKey: "invalid_key",
};

const data = "Hello, world!";

crypto
  .publicEncrypt(keyPair.publicKey, Buffer.from(data))
  .then((encryptedData) => {
    console.log(encryptedData); // Will throw an error
  })
  .catch((err) => {
    console.error(err);
  });

Potential Applications:

Secure communication between servers and clients
Data encryption for storage and transmission
Authentication and authorization

ERR_CRYPTO_INVALID_KEYTYPE

Explanation:

When you're using a crypto library to encrypt or decrypt something, you need to provide a key. This key is like a secret code that tells the library how to do its job. The key type is the type of code used, like a password or a certificate.

If you give the library the wrong type of key, it can't do its job and it gives this error.

Example:

const crypto = require("crypto");

const key = "my-password"; // This is a password, but the library needs a certificate
const data = "secret data";

crypto.encrypt(key, data); // This will throw the error

Real-World Applications:

Encrypting and decrypting confidential data, such as user passwords or financial information.
Verifying the authenticity of digital signatures.
Generating and exchanging secure keys for communication.

Potential Improvements:

The error message could be more specific, explaining which key type is expected and why the provided key is invalid.

Here's an improved error message:

Error: ERR_CRYPTO_INVALID_KEYTYPE: The provided key is not a valid certificate. A certificate is required for this operation.

`ERR_CRYPTO_INVALID_MESSAGELEN`

Simplified Explanation:

You tried to use a function that requires a specific length for its input, but the input you provided was too short or too long.

Code Snippet:

const crypto = require("crypto");
const algorithm = "aes-256-cbc";
const key = "my secret key";
const iv = "my initialization vector";

const message = "Hello, world!";

try {
  const cipher = crypto.createCipheriv(algorithm, key, iv);
  const encryptedMessage = cipher.update(message);
} catch (err) {
  if (err.code === "ERR_CRYPTO_INVALID_MESSAGELEN") {
    console.log("Invalid message length.");
  }
}

Real-World Example:

When encrypting data using the AES-256-CBC algorithm, the message length must be a multiple of 16 bytes. If you try to encrypt a message that is not a multiple of 16 bytes, you will get this error.

Potential Applications:

Securely encrypting data for storage or transmission
Protecting user passwords and other sensitive information

`ERR_CRYPTO_INVALID_SCRYPT_PARAMS`

Simplified Explanation:

When using the scrypt function to generate a key, you must provide valid parameters. If you provide invalid parameters, you will get this error.

Code Snippet:

const crypto = require("crypto");
const scryptOptions = {
  length: 32,
  salt: "my salt",
  iterations: 10000,
};

try {
  const key = crypto.scryptSync("my password", scryptOptions);
} catch (err) {
  if (err.code === "ERR_CRYPTO_INVALID_SCRYPT_PARAMS") {
    console.log("Invalid scrypt parameters.");
  }
}

Real-World Example:

When hashing a password using scrypt, you must provide valid parameters for the function. If you provide invalid parameters, the password will not be hashed securely and could be easily cracked.

Potential Applications:

Hashing passwords for user authentication
Protecting sensitive data

Topic 1: ERR_CRYPTO_INVALID_SCRYPT_PARAMS

Simplified Explanation:

You're trying to use a password-encrypting technique called "scrypt" with the wrong settings. It's like trying to use the wrong key to open a door.

Code Snippet:

const crypto = require("crypto");

try {
  crypto.scryptSync("myPassword", "mySalt", 10);
} catch (err) {
  // Error: ERR_CRYPTO_INVALID_SCRYPT_PARAMS
}

Real-World Application:

Encrypting passwords for online accounts

Topic 2: ERR_CRYPTO_INVALID_STATE

Simplified Explanation:

You're trying to use a cryptographic operation on an object that's in the wrong state. It's like trying to use a car that's not turned on.

Code Snippet:

const crypto = require("crypto");

const cipher = crypto.createCipher("aes-256-cbc", "myPassword");

try {
  cipher.update("myMessage");
} catch (err) {
  // Error: ERR_CRYPTO_INVALID_STATE
}

Real-World Application:

Encrypting data for secure storage or transmission

`ERR_CRYPTO_INVALID_STATE`

Explanation:

Just like you need to bake a cake step-by-step, using a cryptography function also follows specific steps (like adding ingredients and baking it). If you try to do things out of order (like eating the cake before it's baked), you'll get this error.

Example:

Imagine you're using a cipher (a device that encrypts and decrypts data) to scramble a message. You first need to feed the cipher with the message (cipher.update()), then tell it you're finished (cipher.final()), and only then can you ask for the encrypted result (cipher.getAuthTag()). If you skip cipher.final() and try to get the result directly, you'll get this error.

Code Example:

const crypto = require("crypto");

const cipher = crypto.createCipher("aes-256-cbc", "my_secret_key");

cipher.update("Hello, world!"); // Feed the cipher the message

// Oops! We skipped `cipher.final()` and went straight to getting the result
const result = cipher.getAuthTag(); // This will throw ERR_CRYPTO_INVALID_STATE

// The correct way to get the result
cipher.final(); // Tell the cipher we're finished
const result = cipher.getAuthTag(); // Get the encrypted result

Real-World Applications:

Secure communication (encrypting messages sent over the internet)
Data encryption (storing sensitive data in an encrypted format)
Digital signatures (verifying the authenticity of messages)

ERR_CRYPTO_INVALID_TAG_LENGTH

Simplified Explanation:

Imagine you're playing a secret code game with a friend. You use a special key to encrypt messages so only your friend can read them.

But oh no! You made a mistake. You used the wrong key, or you forgot to add the right number of secret code words at the end of the message. Now your friend can't unlock the message because it's like a puzzle with missing pieces.

That's what happens with ERR_CRYPTO_INVALID_TAG_LENGTH. It means there was a problem with the secret code words at the end of the message, and the code can't be unlocked.

Code Example:

const crypto = require("crypto");

const key = "secret-key";
const message = "Hello World";

// Encrypt the message with the wrong key or tag length
try {
  const encrypted = crypto.encrypt("aes-256-gcm", message, Buffer.from(key));
  console.log("Encrypted message:", encrypted.toString());
} catch (err) {
  // Error handling
  if (err.code === "ERR_CRYPTO_INVALID_TAG_LENGTH") {
    console.error("Invalid tag length. Encryption failed.");
  } else {
    throw err;
  }
}

Potential Applications:

Secure communication, such as:

Encrypting messages in email or messaging apps
Protecting data in online banking and e-commerce
Safeguarding sensitive data in healthcare and government systems

`ERR_CRYPTO_JOB_INIT_FAILED`

When you're using Node.js to do something secure, like encrypting a message, it sometimes needs to start up a special process called a "crypto job" to help it do the work. But sometimes, that crypto job can't get started for some reason. This error means that the crypto job couldn't be started, and so the secure operation couldn't be completed.

Here's an example of how this error might look in code:

try {
  const encryptedMessage = crypto.encrypt('aes-256-cbc', 'my password', 'my message');
} catch (err) {
  if (err.code === 'ERR_CRYPTO_JOB_INIT_FAILED') {
    // Handle the error
  }
}

In this example, we're trying to encrypt a message using the crypto module. If the crypto.encrypt() function can't start up the crypto job, it will throw an error with the code ERR_CRYPTO_JOB_INIT_FAILED.

Potential applications:

Encrypting messages for secure communication
Generating digital signatures for authenticating documents
Verifying the integrity of data using hash functions

`ERR_CRYPTO_JWK_UNSUPPORTED_CURVE`

Explanation

When you're using a key in a JSON Web Token (JWT), the key must use a specific type of curve. If the key doesn't use the correct curve, you'll get this error.

Simplified Explanation

Imagine you're building a fort with blocks that have different shapes. The blocks have to fit together in a certain way to make the fort strong. If you try to use a block with the wrong shape, the fort won't be strong and might fall apart.

In the same way, JWT keys have to use the correct curve to work properly. If you try to use a key with the wrong curve, the JWT won't be secure and might be easy to break.

Real-World Example

JWTs are used to securely store user information in web applications. For example, a JWT might contain information about a user's name, email address, and role. When a user logs into a website, the website sends them a JWT that contains this information. The website can then use the JWT to verify that the user is logged in and to grant the user access to the appropriate parts of the website.

If a JWT doesn't use the correct curve, it could be easy for an attacker to break the JWT and gain access to the user's information. This is why it's important to make sure that JWTs use the correct curve.

Potential Applications

JWTs are used in a variety of web applications, including:

Authentication and authorization
Single sign-on
Data exchange
API security

Improved Code Example

const jwk = {
  kty: "EC",
  crv: "P-256",
  x: "...",
  y: "...",
  d: "...",
};

const jwt = createJWT({
  header: {
    alg: "ES256",
  },
  payload: {
    sub: "user@example.com",
  },
  key: jwk,
});

Simplified Explanation of `ERR_CRYPTO_JWK_UNSUPPORTED_KEY_TYPE`

What is JSON Web Key Types Registry?

It's like a special book that lists all the different types of keys that can be used for certain security tasks.

What is ERR_CRYPTO_JWK_UNSUPPORTED_KEY_TYPE?

It's an error that happens when you try to use a key that's not listed in the JSON Web Key Types Registry.

In plain English:

You're trying to use a key that's not allowed for a certain task. It's like trying to open a door with the wrong key.

Real World Example

Imagine you have a safe with two locks. One lock uses a regular key, and the other uses a special key. If you try to open the lock with the regular key, it won't work because the keys aren't compatible.

Code Example

const crypto = require('crypto');

// Create a key that's not registered in the registry
const key = crypto.createPublicKey({
  type: 'unknown',
  key: '...'
});

// Trying to use the key will throw the `ERR_CRYPTO_JWK_UNSUPPORTED_KEY_TYPE` error
const result = crypto.verify(...);

Potential Applications

Securely storing and transmitting sensitive information
Authenticating users
Encrypting and decrypting data

Error: ERR_CRYPTO_OPERATION_FAILED

This error means that a cryptographic operation failed for an unknown reason. Cryptographic operations are used to encrypt and decrypt data, generate secure random numbers, and verify digital signatures.

Real-World Application

Encryption: Sending sensitive data over the internet.
Decryption: Accessing encrypted files or messages.
Authentication: Verifying the identity of a user.

Code Example

try {
  const cipher = crypto.createCipher('aes-256-cbc', 'secret');
  const encryptedData = cipher.update('Hello, world!', 'utf8');
  encryptedData += cipher.final();
} catch (err) {
  if (err.code === 'ERR_CRYPTO_OPERATION_FAILED') {
    console.error('Cryptographic operation failed!');
  } else {
    throw err;
  }
}

Simplified Explanation

Imagine you have a secret box that you want to lock and unlock with a key. The key is the cryptographic operation, and it allows you to perform actions on the box. If the key is not working correctly, you won't be able to access or modify the box.

ERR_CRYPTO_PBKDF2_ERROR

Explanation:

Imagine you're trying to make a secret password. You use a special math formula called "PBKDF2" to mix together your password and a random number. But something goes wrong and the formula doesn't work as it should.

Code Snippet:

try {
  crypto.pbkdf2(
    password,
    salt,
    iterations,
    keylen,
    digest,
    (err, derivedKey) => {
      if (err) {
        if (err.message === "ERR_CRYPTO_PBKDF2_ERROR") {
          // The PBKDF2 algorithm failed for unspecified reasons.
        }
      }
    }
  );
} catch (err) {
  if (err.message === "ERR_CRYPTO_PBKDF2_ERROR") {
    // The PBKDF2 algorithm failed for unspecified reasons.
  }
}

Applications:

PBKDF2 is used to generate secure passwords for applications such as:

Online banking
Email services
Social media platforms

`ERR_CRYPTO_SCRYPT_INVALID_PARAMETER`

Explanation:

When using the crypto.scrypt() or crypto.scryptSync() functions, you must provide certain parameters. If any of these parameters are not within the allowed range, you will get this error.

Simplified Example:

Imagine you are making a cake. The recipe says to use 2 cups of flour. If you accidentally put in 5 cups of flour, the cake will not turn out well. This is similar to what happens when you provide invalid parameters to crypto.scrypt().

Code Snippets:

// Incorrect: Using an invalid value for the 'salt' parameter
const invalidSalt = "";
crypto.scrypt("password", invalidSalt, 64, (err, key) => {});

// Correct: Using a valid value for the 'salt' parameter
const validSalt = "your_salt_here";
crypto.scrypt("password", validSalt, 64, (err, key) => {});

Real-World Applications:

crypto.scrypt() is used to generate secure passwords. If you use invalid parameters, the passwords generated will not be secure.

`ERR_CRYPTO_SCRYPT_NOT_SUPPORTED`

Explanation:

Your system does not support the crypto.scrypt() function. This can happen if you are using an older version of Node.js or if your operating system does not have the necessary libraries installed.

Simplified Example:

Imagine you want to play a video game, but your computer does not have the required graphics card. You will not be able to play the game. Similarly, if crypto.scrypt() is not supported on your system, you will not be able to use it.

Code Snippets:

try {
  // Try to use the 'crypto.scrypt()' function
  crypto.scrypt("password", "salt", 64, (err, key) => {});
} catch (err) {
  // Catch the 'ERR_CRYPTO_SCRYPT_NOT_SUPPORTED' error
  if (err.code === "ERR_CRYPTO_SCRYPT_NOT_SUPPORTED") {
    console.log(
      'The "crypto.scrypt()" function is not supported on your system.'
    );
  } else {
    // Handle other errors
  }
}

Real-World Applications:

If your application requires the use of crypto.scrypt(), you should check if it is supported on the user's system before using it.

`ERR_CRYPTO_SCRYPT_NOT_SUPPORTED`

Plain English Explanation

Imagine you have a secret message you want to keep safe. You could use a password to encrypt it, but that's not very secure. Instead, you can use a special function called "scrypt" to make it much harder to break.

Unfortunately, sometimes your computer doesn't have the "scrypt" function installed. This means you can't use it to encrypt your secret message, and your message might not be safe.

Code Example

const crypto = require("crypto");

// Try to create a scrypt key
crypto.createScrypt("password", "salt", 32, (err, key) => {
  if (err) {
    // Handle the error
    if (err.code === "ERR_CRYPTO_SCRYPT_NOT_SUPPORTED") {
      console.log("Scrypt is not supported on this system.");
    } else {
      console.log("Unknown error:", err);
    }
  } else {
    // The key was created successfully
  }
});

Real-World Applications

Encrypting sensitive data for storage
Protecting passwords and other credentials
Verifying digital signatures
Generating random numbers for security purposes

Potential Applications

Secure messaging apps
Password management systems
Cryptographic libraries
Blockchain technology

Simplified Explanation

ERR_CRYPTO_SIGN_KEY_REQUIRED

Meaning: When you want to sign a message, you need to provide a key. It's like a secret code that helps you prove that the message came from you.

Real-World Example:

Imagine you're sending a letter to your friend. To prove it's really from you, you sign the bottom with your name. If you didn't sign it, your friend wouldn't know if it was really from you.

Code Example:

// This will throw ERR_CRYPTO_SIGN_KEY_REQUIRED
const crypto = require("crypto");
crypto.sign("sha256", "My message");

To fix the error, you can provide a key when you call the sign method:

const crypto = require("crypto");
const key = "My secret key"; // Replace with your actual key
crypto.sign("sha256", "My message", { key: key });

Node.js Error: ERR_CRYPTO_TIMING_SAFE_EQUAL_LENGTH

Simplified Explanation:

When you try to check if two pieces of data are equal using the crypto.timingSafeEqual() function, the lengths of the data must be the same. If the lengths are different, you'll get this error.

Technical Details:

crypto.timingSafeEqual() is used to compare data securely, ensuring that the amount of time it takes to compare the data does not reveal any information about the data itself. This protection against timing attacks is important for sensitive data, such as passwords or encryption keys.

Code Snippets:

Incorrect:

const data1 = Buffer.from("hello");
const data2 = Buffer.from("world");

crypto.timingSafeEqual(data1, data2); // Error: ERR_CRYPTO_TIMING_SAFE_EQUAL_LENGTH

Correct:

const data1 = Buffer.from("hello");
const data2 = Buffer.from("hello");

crypto.timingSafeEqual(data1, data2); // No error

Real-World Applications:

Protecting passwords against hackers who may try to guess the password based on the time it takes to compare it.
Ensuring that encryption keys are securely compared in cryptographic operations.
Preventing attackers from obtaining sensitive information by analyzing the execution time of data comparisons.

ERR_CRYPTO_UNKNOWN_CIPHER

Simplified Explanation:

You tried to use a secret code (called a cipher) that your computer doesn't know about. It's like trying to speak a secret language that your friend doesn't understand.

Code Snippet:

const crypto = require("crypto");

try {
  crypto.createCipher("unknown_cipher", "my_password"); // This will throw ERR_CRYPTO_UNKNOWN_CIPHER
} catch (error) {
  console.error("Error:", error.message); // Log the error message
}

Real-World Application:

Encrypting and decrypting sensitive information, such as credit card numbers or passwords.

ERR_CRYPTO_UNKNOWN_DH_GROUP

Simplified Explanation:

You tried to use a special trick (called a Diffie-Hellman group) to share a secret between two computers, but your computer doesn't know about the trick you're trying to use. It's like trying to follow a magician's instructions without knowing the trick.

Code Snippet:

const tls = require("tls");

try {
  const serverOptions = {
    dhparam: "unknown_dh_group.pem", // This file should contain the DH group parameters
  };

  tls.createServer(serverOptions); // This will throw ERR_CRYPTO_UNKNOWN_DH_GROUP
} catch (error) {
  console.error("Error:", error.message); // Log the error message
}

Real-World Application:

Establishing secure connections between two computers, such as a website and a user's browser.

What is ERR_CRYPTO_UNKNOWN_DH_GROUP?

Imagine you and your friend want to send each other a secret message. You agree to use a special code to encrypt the message so that no one else can read it.

In this code, you and your friend decide to use a secret key that is created using a special mathematical equation called a Diffie-Hellman group. This group is like a special set of numbers that you and your friend use to create the secret key.

However, if you and your friend use a Diffie-Hellman group that is not supported by the code you are using, you will get the ERR_CRYPTO_UNKNOWN_DH_GROUP error. This means that the code doesn't understand the group you are trying to use.

How to fix ERR_CRYPTO_UNKNOWN_DH_GROUP:

To fix this error, you need to use a Diffie-Hellman group that is supported by the code you are using. You can find a list of supported groups in the documentation for the crypto.getDiffieHellman() function.

Real-world example:

Imagine you are building a messaging app that uses encryption to keep messages private. You want to use the Diffie-Hellman algorithm to create secret keys for each conversation.

If you try to use a Diffie-Hellman group that is not supported by the encryption library you are using, you will get the ERR_CRYPTO_UNKNOWN_DH_GROUP error. To fix this, you would need to use a supported group instead.

Potential applications:

The Diffie-Hellman algorithm is used in many real-world applications, including:

Secure messaging apps
VPNs (virtual private networks)
Online banking
E-commerce

`ERR_CRYPTO_UNSUPPORTED_OPERATION` Error

Simplified Explanation: You tried to use a feature in Node.js's cryptography (secret code handling) system that isn't supported on your computer or operating system. It's like trying to use a special tool that your computer doesn't have.

Real-World Example: Imagine you're building a secret code vault and you want to use a high-tech encryption algorithm to keep the secrets safe. But your computer only supports basic encryption, so you can't use the fancy algorithm. Instead, you have to use the simpler one.

Code Example:

const crypto = require("crypto");

try {
  crypto.createHmac("sha512", "secret"); // Attempt to use an unsupported algorithm
} catch (err) {
  // Catch the error and handle it appropriately, like displaying a message to the user
}

Potential Applications:

Securing secret data in applications (passwords, bank account numbers, etc.)
Encrypting and decrypting files

ERR_DEBUGGER_ERROR

Explanation:

This error occurs when there is a problem with the debugger, which is a tool that helps you check for issues in your code.

Simplified Explanation:

Imagine you have a toy car that you want to fix. You use a tool called a debugger to see what's wrong with the car. But if the debugger itself is broken, you won't be able to fix the car. That's what happens with ERR_DEBUGGER_ERROR: your debugger isn't working, so you can't find out what's wrong with your code.

Real-World Example:

Let's say you have a website that you're building. You add a new feature to the website, but it's not working properly. You use a debugger to try and find the problem, but the debugger itself stops working. This would cause an ERR_DEBUGGER_ERROR.

Potential Applications:

Debugging code in any programming language
Troubleshooting issues in software applications
Finding bugs in websites

Code Snippet:

try {
  // Start the debugger
  debugger;
} catch (err) {
  // Handle the ERR_DEBUGGER_ERROR
  if (err.code === "ERR_DEBUGGER_ERROR") {
    console.error("There is a problem with the debugger.");
  } else {
    throw err;
  }
}

Improvements:

The code snippet can be improved by providing a more specific error message, such as:

if (err.code === "ERR_DEBUGGER_ERROR") {
  console.error("Could not start the debugger due to an internal error.");
}

Instead of catching the error, you can use the debug module to listen for the 'debuggerError' event, which will be emitted when an ERR_DEBUGGER_ERROR occurs. This allows you to handle the error in a more customized and asynchronous manner.

ERR_DEBUGGER_STARTUP_ERROR

When you're trying to use the debugger in Node.js, the debugger needs to connect to a specific port on your computer. If that port is already being used by another program or service, the debugger will give up after a certain amount of time and throw this error.

Here's a simplified explanation:

Imagine you're trying to connect to a friend's house, but your friend's door is already open and someone else is inside. The debugger is like a guest who is trying to enter the house, but if the house is already occupied, the guest will have to wait outside until the other person leaves.

Real-world example:

You're trying to debug a Node.js script on your computer, but you forgot that you already have another program running that is using the same port as the debugger. When you try to start the debugger, it will fail with this error.

Solution:

To fix this error, you can try closing the other program that is using the port, or you can change the port that the debugger is using. To change the port, you can use the --debug-port command-line option when starting Node.js, like this:

node --debug-port=9229 script.js

Potential applications in the real world:

The debugger is a useful tool for troubleshooting problems with your Node.js code. By using the debugger, you can step through your code line by line and inspect the values of variables to see what's going wrong.

`ERR_DLOPEN_DISABLED`

When you want to load some native code into your JavaScript program, you need to use a special function called dlopen(). This function is used to open up a shared library on your computer that contains the native code that you want to use.

However, sometimes you might not want to load any native code into your program. For example, you might be running your program on a computer that doesn't have the necessary libraries installed, or you might be trying to use a library that is known to be unstable or insecure.

In these cases, you can use the --no-addons flag when you start your program. This flag will disable the dlopen() function and prevent your program from loading any native code.

Here's a simplified example of how you can use the --no-addons flag:

node --no-addons my-program.js

This command will start the Node.js program my-program.js with the --no-addons flag enabled. This will prevent the program from loading any native code, even if it tries to do so using the dlopen() function.

`ERR_DLOPEN_FAILED`

The ERR_DLOPEN_FAILED error is thrown when the dlopen() function fails to open a shared library on your computer. This can happen for a number of reasons, such as:

The shared library doesn't exist on your computer.
The shared library is not compatible with your version of Node.js.
The shared library is corrupt or damaged.

In order to fix this error, you need to make sure that the shared library you are trying to load is installed on your computer and that it is compatible with your version of Node.js. You may also need to check the shared library for any errors or corruption.

Here's a simplified example of how you can fix the ERR_DLOPEN_FAILED error:

// Check if the shared library is installed on your computer.
if (!fs.existsSync('/path/to/shared_library.so')) {
  throw new Error('The shared library does not exist on your computer.');
}

// Check if the shared library is compatible with your version of Node.js.
if (process.versions.node !== '16.13.0') {
  throw new Error('The shared library is not compatible with your version of Node.js.');
}

// Check if the shared library is corrupt or damaged.
try {
  dlopen('/path/to/shared_library.so');
} catch (error) {
  throw new Error('The shared library is corrupt or damaged.');
}

This code snippet will perform a number of checks to make sure that the shared library you are trying to load is installed, compatible, and not corrupt. If any of these checks fail, the code will throw an error.

`ERR_DLOPEN_FAILED`

Simplified Explanation:
- When you try to load a code library from another file into your program, and it fails.
Detailed Explanation:
- process.dlopen() is a function used to load a dynamic link library (DLL) into your Node.js program. If the library cannot be found or loaded successfully, it will throw an ERR_DLOPEN_FAILED error.

Code Snippet:

const lib = process.dlopen("my_library.so");

Real-World Implementation:
- Loading third-party libraries to extend the functionality of your program, such as a library for image processing or database connectivity.
Potential Applications:
- Building modular applications where different parts can be loaded and unloaded as needed.
- Integrating libraries written in other languages (e.g., C/C++) into Node.js programs.

`ERR_DIR_CLOSED`

This error is thrown when you try to use a fs.Dir object that has been closed. A fs.Dir object is used to read the contents of a directory. When you are finished reading the contents of a directory, you should close the fs.Dir object to free up resources.

Here is an example of how to use a fs.Dir object:

const fs = require("fs");

const dir = fs.opendirSync("/tmp");

while (true) {
  const dirent = dir.readSync();
  if (!dirent) break;

  console.log(dirent.name);
}

dir.closeSync();

If you try to use the dir object after it has been closed, you will get an ERR_DIR_CLOSED error.

`ERR_DIR_CONCURRENT_OPERATION`

This error is thrown when you try to perform multiple concurrent operations on a fs.Dir object. For example, you cannot read from a fs.Dir object while you are also writing to it.

Here is an example of how to avoid getting an ERR_DIR_CONCURRENT_OPERATION error:

const fs = require("fs");

const dir = fs.opendirSync("/tmp");

// Read from the directory
while (true) {
  const dirent = dir.readSync();
  if (!dirent) break;

  console.log(dirent.name);
}

// Write to the directory
fs.writeFileSync("/tmp/foo", "bar");

dir.closeSync();

In this example, we first read from the directory and then write to it. We do not try to perform multiple concurrent operations on the directory, so we will not get an ERR_DIR_CONCURRENT_OPERATION error.

What is ERR_DIR_CONCURRENT_OPERATION?

When you're reading or closing a directory in Node.js, you shouldn't be trying to do other things with that directory at the same time. This error means you're trying to read a directory while it's also being modified.

Simplified Explanation:

Imagine you have a library book. You're reading the book and someone else comes and tries to take the book away while you're still reading it. That would be a concurrent operation. You can't read the book properly if someone is taking it away at the same time.

Real-World Example:

Here's a code example that would trigger the ERR_DIR_CONCURRENT_OPERATION error:

const fs = require("fs");

const dir = fs.opendirSync("my-directory");
// Do some other stuff...
dir.readSync(); // This will cause the error

In this example, we're opening a directory for reading and then trying to read it while we're doing other stuff. This causes the error because you can't read and modify a directory at the same time.

Potential Applications:

Avoiding this error is important in any application that uses Node.js to work with directories. If you're not careful, you can corrupt your data or cause other problems if you try to access a directory while it's being modified.

Simplified Explanation:

ERR_DNS_SET_SERVERS_FAILED error occurs when your program tries to set the Domain Name System (DNS) servers it uses to find websites and other internet resources but fails to do so. DNS servers are like address books for the internet.

Detailed Explanation:

DNS servers are computers that translate human-readable website names (like "www.example.com") into IP addresses (like "1.2.3.4"). When your program tries to connect to a website, it uses the configured DNS servers to find the IP address associated with that website.

If your program fails to set the DNS servers, it won't be able to translate website names into IP addresses and will therefore be unable to access the internet.

Code Snippet:

const dns = require('dns');

dns.setServers(['8.8.8.8', '8.8.4.4']);

// If setting the DNS servers fails, the code below will throw an ERR_DNS_SET_SERVERS_FAILED error
dns.lookup('www.example.com', (err, address) => {
  if (err) {
    console.log(err);
  } else {
    console.log('Address:', address);
  }
});

Real-World Applications:

Web Browsing: When you type a website address into your browser, it uses DNS servers to find the IP address of the website and connect to it.
Email Communication: When you send an email, DNS servers translate the recipient's email address into an IP address for the email server.
Online Gaming: When you play online games, DNS servers help your computer find the IP address of the game server.

Potential Applications:

Custom DNS Filtering: You could create a program that sets custom DNS servers to block access to certain websites or content.
DNS Server Monitoring: You could develop a monitoring tool that checks the availability and performance of DNS servers.
Automated DNS Server Configuration: You could build a script that automatically sets the optimal DNS servers for your network based on factors like speed and reliability.

Simplified Explanation of `ERR_DOMAIN_CALLBACK_NOT_AVAILABLE`

What is it?

It's an error that means you can't use the domain module to handle errors in your Node.js program.

Why does it happen?

This error happens when you call the process.setUncaughtExceptionCaptureCallback() function before using the domain module.

What does it mean?

When you call process.setUncaughtExceptionCaptureCallback(), you're telling Node.js to handle uncaught errors in a specific way. This means that the domain module can't handle errors anymore.

How to fix it?

You can fix this error by not calling process.setUncaughtExceptionCaptureCallback() before using the domain module.

Real-World Example

Here's an example of code that would trigger this error:

// This function is used to handle uncaught errors in a specific way.
function customErrorHandler(err) {
  console.error(err.stack);
}

// Call the `process.setUncaughtExceptionCaptureCallback()` function to use
// the custom error handler.
process.setUncaughtExceptionCaptureCallback(customErrorHandler);

// Try to create a domain and catch any errors that occur within it.
const domain = require("domain");
const d = domain.create();

// This function will throw an error inside the domain.
d.run(function () {
  throw new Error("This is an error!");
});

When you run this code, you'll get the following error:

ERR_DOMAIN_CALLBACK_NOT_AVAILABLE

This error is because you called process.setUncaughtExceptionCaptureCallback() before creating the domain. To fix it, you would need to move the call to process.setUncaughtExceptionCaptureCallback() after creating the domain, like this:

// Create a domain to catch errors.
const domain = require("domain");
const d = domain.create();

// Call the `process.setUncaughtExceptionCaptureCallback()` function to use
// the custom error handler.
process.setUncaughtExceptionCaptureCallback(customErrorHandler);

// This function will throw an error inside the domain.
d.run(function () {
  throw new Error("This is an error!");
});

Now, when you run this code, the error will be caught by the custom error handler and printed to the console.

Potential Applications

The domain module can be used to handle errors in a more controlled way. For example, you could use it to:

Log errors to a file or database.
Send errors to a remote logging service.
Retry operations that fail due to errors.

`ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE`

When you try to set a callback for uncaught exceptions using process.setUncaughtExceptionCaptureCallback(), but you have already loaded the node:domain module.

const { setUncaughtExceptionCaptureCallback } = require('process');

// Loading the 'node:domain' module
require('domain');

// Trying to set a callback for uncaught exceptions
setUncaughtExceptionCaptureCallback((err) => {
  console.log(err.message);
});

Explanation:

The node:domain module is a legacy API that provides a way to handle exceptions using domains.
When you load the node:domain module, it modifies the behavior of how exceptions are handled.
This can conflict with the newer process.setUncaughtExceptionCaptureCallback() API, which allows you to set a callback for all uncaught exceptions.
To avoid this conflict, you should not load the node:domain module if you want to use process.setUncaughtExceptionCaptureCallback().

Other Potential Errors

ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE
ERR_DOMAIN_IN_UNWIND_STACK
ERR_DOMAIN_NO_ACTIVE
ERR_DOMAIN_NO_ACTIVE_OR_EXISTING_REQUIRED
ERR_DOMAIN_NO_STACK_TRACE
ERR_DOMAIN_PLATFORM_NOT_SUPPORTED
ERR_DOMAIN_UNBOUND_VALUE

Real-World Applications

Exception handling is an important part of any application.
By using the process.setUncaughtExceptionCaptureCallback() API, you can ensure that all uncaught exceptions are handled in a consistent manner.
This can help you to improve the stability and reliability of your application.

Simplified Explanation

`ERR_DUPLICATE_STARTUP_SNAPSHOT_MAIN_FUNCTION`

What is it?

It's an error that occurs when you try to set the main function for a startup snapshot more than once.

Why does it happen?

Each startup snapshot can only have one main function. If you try to set it multiple times, you'll get this error.

Code Snippet:

const { setDeserializeMainFunction } = require("v8.startupSnapshot");

// Set the main function for the startup snapshot.
setDeserializeMainFunction(() => {});

// Try to set the main function again.
setDeserializeMainFunction(() => {}); // Error: ERR_DUPLICATE_STARTUP_SNAPSHOT_MAIN_FUNCTION

Potential Applications:

Startup snapshots are used to reduce the startup time of applications. By providing a pre-compiled snapshot, the application can start up much faster. The main function is a special function that is called when the application starts up. It's usually used to initialize the application and load any necessary data.

Simplified Explanation:

When you try to convert data into text using special codes called "encodings," and you give it wrong codes, the computer gets confused and throws this error.

Technical Explanation:

ERR_ENCODING_INVALID_ENCODED_DATA: Occurs when data is provided to TextDecoder(), a JavaScript API for decoding data, and the encoding specified is invalid for the data provided.
ERR_ENCODING_NOT_SUPPORTED: Occurs when the specified encoding is not supported by the platform.

Real-World Example:

Imagine you have a text file with the message "Hello, world!" encoded in ASCII. If you try to decode it using UTF-8 encoding, which is not the correct encoding, you will get ERR_ENCODING_INVALID_ENCODED_DATA.

// Incorrect encoding - UTF-8 instead of ASCII
const decoder = new TextDecoder("utf-8");
const data = decoder.decode(encodedData); // Error: ERR_ENCODING_INVALID_ENCODED_DATA

Potential Applications:

Text processing and decoding in web applications.
File handling and conversion across different systems.
Data validation and sanitization.

Improved Code Snippets:

// Correct encoding - ASCII
const decoder = new TextDecoder("ascii");
const data = decoder.decode(encodedData); // Success - Decodes to "Hello, world!"

// Handling ERR_ENCODING_NOT_SUPPORTED
try {
  const decoder = new TextDecoder("unsupported-encoding");
} catch (e) {
  if (e.code === "ERR_ENCODING_NOT_SUPPORTED") {
    // Handle unsupported encoding error
  }
}

ERR_ENCODING_NOT_SUPPORTED

Meaning:

When you're trying to decode text from a buffer (a chunk of data) using the TextDecoder() API, you must specify the encoding of the text. If you specify an encoding that is not supported by the browser or Node.js, you'll get this error.

Example:

// Using an unsupported encoding
const decoder = new TextDecoder("xyz");
const text = decoder.decode(buffer);

// Error: ERR_ENCODING_NOT_SUPPORTED

Fix:

Use one of the supported encodings, such as 'utf-8', 'utf-16', or 'latin1'.

Real World Applications:

Decoding text data received from a server
Reading text from a file
Parsing JSON data

Simplified Explanation:

Topic: ERR_EVAL_ESM_CANNOT_PRINT

Meaning: When using Node.js to evaluate JavaScript code as a module (--print), it's possible to run into an error if the JavaScript code is written in the newer ECMAScript Module (ESM) format.

Example:

// This code will cause `ERR_EVAL_ESM_CANNOT_PRINT`
node --print 'import { x } from "module.js";'

Improved Example:

// This code avoids the error by using `--eval` instead of `--print`
node --eval 'import { x } from "module.js"; console.log(x);'

Real-World Application:

ESM is a newer standard for writing JavaScript modules that offers better organization and code isolation. However, some older Node.js versions or environments may not fully support ESM, leading to the ERR_EVAL_ESM_CANNOT_PRINT error when trying to evaluate ESM code. To avoid this issue, you can use the --eval flag instead of --print when evaluating ESM code.

Simplified Explanation of `ERR_EVENT_RECURSION`

Imagine you have a button in your house that, when pressed, turns on the lights. If you press the button repeatedly, the lights will turn on and off repeatedly. This is called recursion.

In Node.js, an EventTarget is like a button that can trigger actions when something happens to it. For example, you could have an EventTarget that listens for mouse clicks. When the mouse clicks on the EventTarget, it can trigger an action, such as playing a sound or opening a new window.

The ERR_EVENT_RECURSION error occurs when you try to trigger an action on an EventTarget while it is already in the process of triggering an action. This is like trying to press the button in your house while the lights are already flashing on and off. The button gets confused and doesn't know what to do.

Real-World Example

Consider a website that has a button that opens a new window when clicked. The following code shows how to implement this using an EventTarget:

const button = document.getElementById("button");
const eventTarget = new EventTarget();

eventTarget.addEventListener("click", () => {
  window.open("new-window.html");
});

button.addEventListener("click", () => {
  eventTarget.dispatchEvent(new Event("click"));
});

If you click the button, the new window will open. However, if you quickly click the button again, you will see the ERR_EVENT_RECURSION error. This is because the EventTarget is already in the process of opening the new window when you click it again.

Potential Applications

The ERR_EVENT_RECURSION error can help you prevent accidental infinite loops in your code. For example, if you have a button that starts a process that takes a long time to complete, you could disable the button while the process is running to prevent the user from accidentally starting the process multiple times.

Conclusion

The ERR_EVENT_RECURSION error is a useful tool for preventing infinite loops in your code. By understanding this error, you can write more robust and reliable applications.

Simplified Explanation of `ERR_EXECUTION_ENVIRONMENT_NOT_AVAILABLE`

What is ERR_EXECUTION_ENVIRONMENT_NOT_AVAILABLE?

Imagine you have a set of toys that you can play with. These toys are like the JavaScript code that you can run. But to play with these toys, you need a special playroom, like the Node.js environment. Without this playroom, the toys won't work properly.

Why does this error occur?

This error happens when the toys (JavaScript code) are trying to be used outside of the playroom (Node.js environment). It's like trying to play with your toys in the kitchen or bathroom instead of the playroom. It just doesn't work right.

Real-World Example

Imagine you have a toy car that you want to play with. You take it outside and start pushing it around, but it doesn't move very well because it's meant to be used in a playroom with smooth floors. This is similar to the error occurring when the JavaScript code is not being used in the correct environment.

Potential Applications

This error is important because it helps developers make sure that their code is running in the right place. It can help prevent problems and unexpected behavior in your applications.

Improved Code Example

Here's an example of how the error might be thrown:

const fs = require("fs"); // Node.js file system module

// Try to read a file outside of the Node.js environment
fs.readFile("myfile.txt", (err, data) => {
  if (err) {
    // Check for the specific error
    if (err.code === "ERR_EXECUTION_ENVIRONMENT_NOT_AVAILABLE") {
      // Handle the error gracefully
      console.error("Cannot access files outside of the Node.js environment.");
    }
  }
});

In this example, we try to read a file using the fs module, which is only available in the Node.js environment. If we try to use it outside of that environment, we will get the ERR_EXECUTION_ENVIRONMENT_NOT_AVAILABLE error.

`ERR_FALSY_VALUE_REJECTION`

Simplified Explanation:

Imagine you have a helper, and you ask them to do a chore. You expect them to either finish the chore or tell you why they can't. But what if they just tell you "nothing"? That's confusing!

In Node.js, this helper is a Promise. When a Promise fails, it needs to tell you why. Otherwise, you won't know what went wrong. If the Promise doesn't give you a reason for failing, it's like your helper telling you "nothing," which is frustrating.

Key Point:

A Promise should always provide a reason for failure, even if it's just a simple message like "Failed to complete task."

Example:

// Creating a Promise that rejects with no reason
Promise.reject();

// Using callbackify to convert the Promise to a callback
const callbackify = require("util").callbackify;
callbackify(promise)((err, result) => {
  // The `err` will be `null` because no reason was provided
});

Real-World Applications:

Debugging: A proper error message helps you quickly identify the root cause of a problem.
Logging: When logging errors, a clear message provides valuable information for troubleshooting.
User Experience: In user interfaces, providing a clear error message gives users a better understanding of what went wrong.

Potential Improvements:

Always provide a meaningful error message in your Promise rejections.
Use error handling best practices like try-catch blocks to handle errors gracefully.

Simplified Explanation of ERR_FEATURE_UNAVAILABLE_ON_PLATFORM Error:

Imagine you're trying to use a cool new feature in Node.js. But the computer you're using doesn't have that feature. It's like trying to plug a round peg into a square hole. Instead of working, you get an error message that says ERR_FEATURE_UNAVAILABLE_ON_PLATFORM.

It means that the operating system (like Windows or macOS) doesn't support the feature you're trying to use. So, even though Node.js has the feature, your computer can't access it.

Real-World Example:

Let's say you want to use the fs.copyFile function to copy a file from one location to another. But your computer is running Windows 10, which doesn't support fs.copyFile. You'll get the ERR_FEATURE_UNAVAILABLE_ON_PLATFORM error.

To fix this, you'd need to use a different way to copy the file that's supported on Windows 10, like using the fs.createReadStream and fs.createWriteStream functions.

Potential Applications:

Cross-platform compatibility: When you have code that runs on different operating systems, you need to check if the features you're using are supported on all of them.
Feature updates: As new operating systems and updates are released, they may add support for new features in Node.js. You can check the Node.js documentation to see which features are available on specific platforms.
Native code dependencies: Some Node.js modules rely on native code libraries that may not be available on all platforms. If a module requires a specific native library that's not available on your platform, you'll get the ERR_FEATURE_UNAVAILABLE_ON_PLATFORM error.

`ERR_FS_CP_DIR_TO_NON_DIR`

Simplified Explanation:

You tried to copy a folder (directory) to something that's not a folder, like a file or a link.

Detailed Explanation:

In Node.js, you can use the fs.cp() function to copy files or directories. If you try to copy a directory to a file or a symlink, which is not a directory, you'll get this error.

Example:

const fs = require("fs");

try {
  fs.cp("folder1", "file2"); // This will cause the error
} catch (err) {
  if (err.code === "ERR_FS_CP_DIR_TO_NON_DIR") {
    // Handle the error
  }
}

Real-World Application:

Imagine you have a folder called "Photos" on your computer that contains a bunch of pictures. You want to move these pictures to a new folder called "New Photos." If you try to copy the "Photos" folder to a file called "picture.jpg," you'll get this error because you can't copy a folder to a file.

Simplified Explanation:

ERR_FS_CP_EEXIST Error (File Already Exists):

Imagine you have a box full of toys and want to put a new toy in the box. But when you open the box, you realize that the toy you wanted to add is already inside. The ERR_FS_CP_EEXIST error is like that - you tried to "copy" a file to a folder, but the file already existed there.

ERR_FS_CP_EINVAL Error (Invalid Input):

This error is like when you ask your friend to play a board game, but you only have two pieces instead of the four you need. The ERR_FS_CP_EINVAL error happens when you try to "copy" a file without giving all the necessary information, like the correct path or destination.

Real-World Code Implementation:

// Copying a file
fs.cp("myfile.txt", "newmyfile.txt", (err) => {
  if (err) {
    if (err.code === "EEXIST") {
      // File already exists
    } else if (err.code === "EINVAL") {
      // Invalid input (e.g., invalid path)
    }
  } else {
    // File copied successfully
  }
});

Potential Applications in the Real World:

File Management: Copying files to new locations or creating backups.
Data Processing: Duplicating files for analysis or processing.
Application Development: Copying files for deployment or testing.

Error Code: ERR_FS_CP_EINVAL

Simplified Explanation:

Imagine you're trying to copy a pile of books from one shelf to another. But when you look at the source shelf (src), it's not even a shelf! It's just a box. And when you look at the destination shelf (dest), it's actually a table. You can't copy books to a table!

In-Depth Explanation:

[ERR_FS_CP_EINVAL][fs.cp()] is an error that occurs when you use the fs.cp() function to copy files or directories, but one of the following is true:

The src path doesn't point to a valid file or directory.
The dest path doesn't point to a valid location where you can copy the file or directory.

Real-World Code Example:

const fs = require("fs");

try {
  fs.cp("invalid-src-path", "invalid-dest-path", (err) => {
    if (err) {
      console.error(`Error copying files: ${err.message}`);
    }
  });
} catch (err) {
  console.error(`Error copying files: ${err.message}`);
}

In this example, fs.cp() will throw the ERR_FS_CP_EINVAL error because both src and dest are invalid paths.

Potential Applications:

This error can help prevent you from accidentally copying files to the wrong location or overwriting existing files. For example, you could use it in a script that automatically backs up your important files to a secure location.

What is ERR_HTTP_BODY_NOT_ALLOWED Error?

Imagine you have a box that is "read-only." You can open the box and look inside, but you can't put anything into it.

The ERR_HTTP_BODY_NOT_ALLOWED error is like trying to put something into a "read-only" box. An HTTP response is like a box that can hold data (like a website or file). When you try to write data (like uploading a file) into a response that doesn't allow data, it throws this error.

Code Example:

const http = require("http");

const server = http.createServer((req, res) => {
  res.writeHead(405); // "Method Not Allowed"
  res.end("This response does not allow writing.");
});

server.listen(3000);

Real-World Applications:

Websites that only allow reading data (like news articles or search results).
Files that are not meant to be modified by the user (like system files or software updates).
APIs that only provide information (like weather data or stock prices).

How to Fix It:

To fix this error, make sure that you are only trying to write data into a response that allows it. For example, a form submission should send data to a URL that accepts it.

HTTP Content Length Mismatch Error

Imagine you have a box of chocolates with a label that says it contains 24 chocolates. When you open the box, you find only 12 chocolates. That's a content length mismatch!

The same thing can happen with HTTP responses, which are the messages sent back to your browser after you visit a website. The response has a "content-length" header that tells your browser how many bytes of data to expect. But if the actual data is different, your browser will throw an error called ERR_HTTP_CONTENT_LENGTH_MISMATCH.

Code Example

const fetch = require('node-fetch');

fetch('https://example.com/chocolate')
  .then(res => res.text())
  .then(data => {
    console.log(data.length); // Oops, it's not 24!
  })
  .catch(err => {
    console.log('Error: ', err);
  });

Real-World Application

This error can occur when:

A server sends an incorrect content-length header.
A network issue corrupts the data during transmission.
A malicious actor modifies the response to send extra data.

How to Fix

To resolve this error, first check if the server is sending the correct content-length header. If it is, then the problem may be with your network or a malicious actor. In these cases, you can try refreshing the page or contacting the website's support.

Understanding ERR_FS_CP_FIFO_PIPE

Imagine your computer is like a big library full of books and folders.

fs.cp() is like a special tool that allows you to copy a book from one folder to another. However, sometimes you might try to copy a special type of book called a "named pipe." It's like a tube that connects two folders.

If you try to copy a named pipe, you'll get the error ERR_FS_CP_FIFO_PIPE because this special tool can't copy such books.

Real-World Applications

Copying files from your local computer to a USB drive

Improved Code Snippet

const fs = require("fs");

try {
  fs.cp("file.txt", "new_file.txt", (err) => {
    if (err && err.code === "ERR_FS_CP_FIFO_PIPE") {
      // Handle the error: The file is a named pipe
    }
  });
} catch (err) {
  // Handle the error: The file is a named pipe or there was another issue
}

Simplified Explanation for a Child

Imagine you have a toy box with two compartments. You can move your toys from one compartment to another, but you can't move a toy that is like a secret tunnel connecting the two compartments. That's what ERR_FS_CP_FIFO_PIPE means.

Simplified Explanation:

ERR_FS_CP_NON_DIR_TO_DIR:

What is it? It's an error that occurs when you try to copy a file or any non-directory item to an existing directory using the fs.cp() function.

Why does it happen? Directories are meant to contain files and other directories, not files themselves. So, when you try to copy a file into a directory, it's like trying to put a square peg in a round hole.

How to fix it: You should first create a new directory inside the existing one, and then copy the files into the new directory.

Code Example:

// Step 1: Create a new directory
fs.mkdirSync("new-directory");

// Step 2: Copy the files into the new directory
fs.cpSync("file.txt", "new-directory/file.txt");

Potential Applications:

Organizing files into directories for better file management
Copying files from one location to another within a directory structure
Creating backups of important files

Explanation:

When you try to copy a file or folder using the fs.cp() function in Node.js, you may encounter the ERR_FS_CP_SOCKET error. This error occurs when you try to copy a file or folder to a socket instead of a regular file system path.

Simplified Explanation for a 5-Year-Old Child:

Imagine you have a toy box filled with blocks. You want to copy some blocks from the toy box into a smaller box. But instead of copying the blocks into the smaller box, you try to copy them into a toy train. The toy train is like a socket in this case, and the blocks are like the files or folders you're trying to copy.

Real-World Complete Code Implementation:

const fs = require("fs");

try {
  // Attempt to copy a file to a socket
  fs.cp("file.txt", "net:server.example.com:8080");
} catch (err) {
  // Error handling: `ERR_FS_CP_SOCKET`
  if (err.code === "ERR_FS_CP_SOCKET") {
    console.error("Cannot copy file to a socket.");
  } else {
    // Other errors
    throw err;
  }
}

Potential Applications:

This error is commonly encountered when you're trying to copy files or folders in a web application, such as when uploading files to a server. It's important to ensure that you're not attempting to copy files to sockets, which are network communication endpoints.

`ERR_FS_CP_SYMLINK_TO_SUBDIRECTORY`

This error is thrown when using the fs.cp() function to copy a file or directory, and the dest (destination) path is a symlink (symbolic link) that points to a subdirectory of the src (source) path.

Explanation:

Imagine you have a folder named Documents and a subfolder named important inside it. Now, you create a symlink named important-copy that points to the important folder.

If you try to copy the Documents folder using fs.cp(), and specify important-copy as the dest path, you'll get this error because the symlink points to a subdirectory of the src path (Documents).

Simplified:

You can't copy a folder using a symlink that points to a subfolder inside that folder. It's like trying to put a folder inside a file that's inside itself.

Code Example:

const fs = require("fs");

// Attempt to copy the Documents folder to a symlink pointing to a subfolder
const src = "Documents";
const dest = "important-copy";

try {
  fs.cp(src, dest, (err) => {
    if (err) {
      console.error("Error copying:", err.message);
    } else {
      console.log("Copied successfully.");
    }
  });
} catch (err) {
  console.error("Caught error:", err.message);
}

In this example, the fs.cp() function will throw the ERR_FS_CP_SYMLINK_TO_SUBDIRECTORY error because the dest path is a symlink to a subdirectory of the src path.

Real-World Applications:

This error is commonly encountered when using symlinks to organize files and folders in a specific way and then trying to copy those files or folders. It's important to be aware of this potential error to avoid unexpected behavior or data loss.

ERR_FS_CP_UNKNOWN

Meaning:

You tried to copy a file, but you didn't tell the computer what type of file it was. It's like trying to give a toy to your friend without saying if it's a car or a doll.

Example:

fs.cp('myfile', 'newfile', (err) => {
  if (err) {
    console.error(`Error copying file! ${err.message}`);
  }
});

In this example, we try to copy myfile to newfile, but we don't specify if newfile is a folder or a file. This will cause an error.

Fix:

To fix it, tell the computer if newfile is a folder or a file by adding dir, file, or symlink to the cp function:

fs.cp('myfile', 'newfile', {dir: true}, (err) => {
  if (err) {
    console.error(`Error copying file! ${err.message}`);
  }
});

This time, we specify that newfile is a directory or folder, so the copy will be done correctly.

Real-World Applications:

Copying files or folders from one location to another
Backing up important files and folders
Distributing software and updates

ERR_FS_EISDIR

This error occurs when you try to perform an operation on a path that is actually a directory, but the operation is not allowed on directories. For example, you might try to open a directory for writing, but this is not allowed because directories can only be opened for reading.

Example:

const fs = require("fs");

try {
  fs.writeFileSync("my-directory/file.txt", "Hello world!");
} catch (err) {
  console.error(err); // Error: EISDIR: illegal operation on a directory, writeFileSync 'my-directory/file.txt'
}

Real-world application:

This error can occur in various scenarios, such as:

When you try to create a file in a non-existent directory.
When you try to write to a directory instead of a file.
When you try to delete a directory that is not empty.
When you try to move or rename a directory to a path that already exists.

Simplified Explanation:

Your computer has a special place called a "file system" where it stores all your files, like photos, videos, and documents. Each file has a certain size limit, like how much space it can take up on your computer.

If you try to read a file that's too big for your computer to handle, it will give you an error message called ERR_FS_FILE_TOO_LARGE. This is like trying to fill up a small cup with too much water—it will overflow!

Code Snippet:

try {
  // Attempt to read a large file
  const data = fs.readFileSync("myfile.txt");
} catch (err) {
  if (err.code === "ERR_FS_FILE_TOO_LARGE") {
    // Handle the error
  }
}

Real-World Examples:

Trying to load a video file that's larger than your computer's memory.
Attempting to open a massive spreadsheet that has too many rows or columns.
Saving a file that exceeds the size limit of your storage device, like a USB drive.

Potential Applications:

Ensuring that files do not exceed certain size limits, preventing crashes or errors.
Managing storage space by restricting the size of files that can be stored.
Protecting systems from malicious attacks involving overly large files.

Error: ERR_FS_INVALID_SYMLINK_TYPE

Simplified Explanation:

This error happens when you try to create a special file called a "symlink" using the fs.symlink() or fs.symlinkSync() methods in Node.js, but you provide an invalid type for the symlink.

What is a Symlink?

A symlink is like a shortcut on your computer. It points to another file or folder, but it doesn't actually contain the data itself. When you click on a symlink, it acts like you're opening the actual file or folder it's pointing to.

What's an Invalid Symlink Type?

There are two types of symlinks: "file" and "directory." If you try to create a symlink that points to a file, but you specify the type as "directory," or vice versa, you'll get this error.

Real World Example:

Suppose you have a file called "hello.txt" and you want to create a symlink called "mytext" that points to it.

Correct Code:

fs.symlink("hello.txt", "mytext", "file", (err) => {
  // This callback will be called when the symlink is created
});

Incorrect Code:

If you specify the wrong type for the symlink, you'll get the ERR_FS_INVALID_SYMLINK_TYPE error:

fs.symlink("hello.txt", "mytext", "directory", (err) => {
  // This callback will be called with the error
});

Potential Applications:

Symlinks are useful for:

Organizing your files in a cleaner way
Creating shortcuts to frequently used files
Sharing files and folders between multiple users or computers

Error: Response Headers Already Sent

Meaning: You tried to modify the response headers after the response had already been sent.

How it Works:

Imagine you're baking a cake. Once you put the cake in the oven, you can't add any more ingredients or toppings. Similarly, once you send a response, you can't change the headers.

Avoidance:

Make sure you send all the necessary headers before you send the response.

Example:

// Sending headers before sending the response
response.setHeader("Content-Type", "text/plain");
response.send("Hello, world!");

Applications:

Web servers
APIs
HTTP communication

`ERR_HTTP_INVALID_HEADER_VALUE` error simplified

This error occurs when you try to set an invalid value for an HTTP header. For example, if you try to set the Content-Length header to a negative value, this error will be thrown.

Real-world example:

const http = require("http");

const server = http.createServer((req, res) => {
  // Set the Content-Length header to a negative value
  res.setHeader("Content-Length", -1);

  // This will throw an ERR_HTTP_INVALID_HEADER_VALUE error
  res.end();
});

server.listen(3000);

Potential applications:

This error can be used to validate HTTP headers and ensure that they are set to valid values. This can help to prevent malicious attacks and improve the security of your application.

ERR_HTTP_INVALID_STATUS_CODE

When you send a request to a server, the server sends back a response that includes a status code. This status code indicates the success or failure of the request.

The ERR_HTTP_INVALID_STATUS_CODE error occurs when the status code that the server sends back is outside the normal range of status codes, which is 100 to 999.

For example, if you send a request to a server and the server responds with a status code of 1000, you would get the ERR_HTTP_INVALID_STATUS_CODE error.

Example:

const https = require("https");

const options = {
  hostname: "example.com",
  port: 443,
  path: "/",
  method: "GET",
};

const req = https.request(options, (res) => {
  if (res.statusCode > 999) {
    // Handle the error
  }
});

req.end();

Real-world Applications:

Checking the status codes of responses from servers to ensure that they are valid.
Ensuring that the status codes of responses from servers are within the expected range.
Handling errors that occur when the status codes of responses from servers are invalid.

Simplified Explanation of ERR_HTTP_REQUEST_TIMEOUT

When you make a request to a website, your computer sends a lot of information to the server. This information includes the URL of the website, the data you're submitting (like in a form), and other details. The server then sends a response back to your computer, which displays the website on your screen.

Sometimes, the server takes too long to send a response. This can happen for a variety of reasons, such as:

The server is overloaded with requests
The server is down or experiencing technical difficulties
Your internet connection is slow or unstable

When this happens, your computer will throw an ERR_HTTP_REQUEST_TIMEOUT error. This error tells you that the server did not respond within the expected amount of time.

Code Snippet

try {
  const response = await fetch("https://example.com");
} catch (error) {
  if (error.code === "ERR_HTTP_REQUEST_TIMEOUT") {
    // Handle the error
  }
}

Real-World Examples

You might see this error if you try to load a website that is experiencing high traffic.
You might also see this error if you have a poor internet connection.

Potential Applications

You can use this error to handle situations where the server is not responding quickly enough.
You can also use this error to display a message to the user, such as "The website is taking too long to load."

Simplified Explanation:

ERR_HTTP_SOCKET_ASSIGNED means that you're trying to use a response object that's already been sent.

In-depth Explanation:

When you send a response to a client, the response object is assigned a socket, which is a communication channel between your server and the client.

If you try to use that response object again after it has already been sent, you'll get this error.

Code Example:

const http = require("http");

const server = http.createServer((req, res) => {
  res.writeHead(200);
  res.end();

  // Trying to use the response object again after it has been sent
  res.statusCode = 404;
  res.end(); // This will throw the ERR_HTTP_SOCKET_ASSIGNED error
});

server.listen(3000);

Potential Applications:

This error prevents you from accidentally sending multiple responses to a single request, which can cause unexpected behavior and performance issues.

`ERR_HTTP_SOCKET_ENCODING`

Explanation:

Imagine you have a pipe that carries information, like a phone line. This pipe has a specific way of encoding the information it sends, like English or Spanish.

In HTTP, the "socket" is like this pipe. It carries information between a client (like your browser) and a server (like a website). The client and server agree to use a specific encoding, like UTF-8, to send and receive data.

This error happens when you try to change the encoding of the socket after it has already been established. It's not allowed because both the client and server need to be using the same encoding to understand each other.

Code Snippet (simplified):

const http = require("http");

const server = http.createServer();

server.on("request", (req, res) => {
  // Try to change the socket encoding to "ascii".
  // This will cause the error.
  req.socket.setEncoding("ascii");
});

server.listen(8080);

`ERR_HTTP_TRAILER_INVALID`

Explanation:

In HTTP, trailers are additional information that can be added to the end of a response. These trailers are used for things like specifying the size of the response or the date it was sent.

This error happens when you try to add a trailer to a response that doesn't have a Trailer header. The Trailer header lists the names of the trailers that will be included in the response.

Code Snippet (simplified):

const http = require("http");

const server = http.createServer();

server.on("request", (req, res) => {
  // Try to add a trailer to the response without a `Trailer` header.
  // This will cause the error.
  res.setHeader("Content-Length", 100);
  res.trailer("Date", "Fri, 15 Dec 2022 08:12:00 GMT");
});

server.listen(8080);

Real-World Applications

These errors can occur in web applications when there is a mismatch in the encoding or trailer handling between the client and server. For example:

A client may be sending a request with an invalid encoding, which can cause the server to throw the ERR_HTTP_SOCKET_ENCODING error.
A server may be sending a response with a trailer without a Trailer header, which can cause the client to throw the ERR_HTTP_TRAILER_INVALID error.

`ERR_HTTP_TRAILER_INVALID`

In simple terms:

You tried to add extra information to the end of an HTTP request, but the way you were sending the request didn't allow it.

Technical explanation:

HTTP requests can have a "Trailer" header, which contains information that comes after the main part of the request. However, not all methods of sending requests support using this header. If you try to use it when it's not supported, you'll get this error.

Code example:

const http = require("http");

const request = http.request(
  {
    method: "GET",
    url: "http://example.com",
    headers: {
      Trailer: "Content-MD5",
    },
  },
  (res) => {
    res.on("data", (chunk) => {
      console.log(chunk);
    });
  }
);

request.end();

This code would throw an ERR_HTTP_TRAILER_INVALID error because the GET method doesn't support the Trailer header.

Real-world application:

This error is most likely to occur when developing web applications that communicate with servers using HTTP. Developers need to be aware of the limitations of HTTP request methods to avoid this error.

Potential applications:

Debugging HTTP requests in web applications
Verifying the validity of HTTP requests in servers
Enforcing HTTP request standards and best practices

`ERR_HTTP2_ALTSVC_INVALID_ORIGIN`

Simplified Explanation:

When you try to use a special type of message in HTTP/2 (called an ALTSVC frame) to tell a web browser that it can use a different server for a website, you need to provide a valid web address (origin) for the original website. If you don't provide a valid origin, you'll get this error.

Improved Code Snippet:

const http2 = require("http2");

const server = http2.createServer();

server.on("altsvc", (frame) => {
  // Check if the frame has a valid origin.
  if (!frame.origin) {
    // If the origin is invalid, throw an error.
    const err = new Error("ERR_HTTP2_ALTSVC_INVALID_ORIGIN");
    throw err;
  }

  // Do something with the ALTSVC frame.
});

Real-World Application:

Web browsers can use ALTSVC frames to optimize their performance. For example, if a browser knows that a website is available on a faster server, it can automatically connect to that server instead of the slower one. This can improve the user's browsing experience.

`ERR_HTTP2_ALTSVC_LENGTH`

When using HTTP/2, there is a limit of 16,382 bytes for the payload of ALTSVC frames. If you try to send an ALTSVC frame with a payload larger than this, you will get this error.

A real-world example of this error would be if you were trying to send a large number of alternative service records in a single ALTSVC frame.

To fix this error, you can either reduce the number of alternative service records that you are sending in a single frame, or you can send multiple ALTSVC frames.

Here is an example of how to send multiple ALTSVC frames:

const http2 = require("http2");

const client = http2.connect("https://example.com");

client.on("altsvc", (altsvc) => {
  console.log(altsvc);
});

client.on("error", (err) => {
  if (err.code === "ERR_HTTP2_ALTSVC_LENGTH") {
    // Handle the error
  }
});

client.writeHeaders({
  ":method": "GET",
  ":path": "/",
});

In this example, we are listening for the altsvc event, which is emitted when the server sends an ALTSVC frame. We are also listening for the error event, which is emitted if there is an error sending the request. If the error code is ERR_HTTP2_ALTSVC_LENGTH, we can handle the error appropriately.

Simplified Explanation: ERR_HTTP2_CONNECT_AUTHORITY

What is it?

When you send a special type of request called a "CONNECT" request using the HTTP/2 protocol, you need to include something called the ":authority" pseudo-header. This header tells the server which website you want to connect to.

Why is it important?

Without this ":authority" header, the server won't know which website you're trying to reach and won't be able to connect you.

Example

Imagine you want to visit the website "example.com" using HTTP/2. You would need to send a CONNECT request that looks something like this:

CONNECT example.com:443 HTTP/2

In this request, the ":authority" header is "example.com". This tells the server that you want to connect to the website "example.com" using HTTPS (port 443).

Potential Applications

CONNECT requests are used to establish a connection between two servers, often through a proxy. This allows clients to access resources that may be blocked or restricted. For example, a web browser could use a CONNECT request to access a website that is blocked by a firewall. Another potential application is for load balancing, where a single server acts as a proxy for multiple backend servers.

Error: ERR_HTTP2_CONNECT_PATH

Simplified Explanation:

When you're using HTTP/2 (a way of talking to websites), you can't use the "CONNECT" method with a path (/path/to/resource). It's like trying to use a key that doesn't fit in a lock.

Technical Explanation:

HTTP/2 uses the CONNECT method to establish a secure connection without specifying a specific resource. But it doesn't allow you to include a path, which is used to specify the specific resource you want to access.

Code Example:

// Attempting to make a CONNECT request with a path
const options = {
  method: "CONNECT",
  path: "/my-resource",
};

const request = http2.request(options);
request.on("error", (err) => {
  console.error(err); // Will print "ERR_HTTP2_CONNECT_PATH"
});

Real-World Application:

HTTP/2 is used in various applications, such as:

Secure web browsing: Establishing encrypted connections to websites.
Streaming media: Delivering high-quality video and audio content.
Real-time communication: Facilitating chat, video conferencing, and other interactive services.

Potential Applications:

Securely connecting to remote servers: Creating encrypted tunnels for secure data transfer.
Building real-time multiplayer games: Enabling players to communicate and interact with each other in real time.
Streaming live events: Delivering high-quality, low-latency live video broadcasts.

`ERR_HTTP2_CONNECT_SCHEME`

In simple terms:

When you're using HTTP/2 to make a special kind of request called a "CONNECT" request, you can't add a special "scheme" header.

More detailed explanation:

HTTP/2 is a newer version of HTTP that allows for faster and more efficient communication. One of the new features in HTTP/2 is the ability to make "CONNECT" requests.

CONNECT requests are used to establish a secure connection to a server. For example, you might use a CONNECT request to connect to a secure website using the HTTPS protocol.

When you make a CONNECT request, you can't add a "scheme" header. The scheme header is used to specify the protocol that you're using, such as HTTP or HTTPS.

This is because the scheme is already determined by the fact that you're making a CONNECT request. The server knows that you're trying to establish a secure connection, so there's no need to specify the scheme in the header.

Code example:

const http2 = require('http2');

const client = http2.connect('https://example.com:443');

client.on('connect', () => {
  // The CONNECT request was successful.
});

client.on('error', (err) => {
  // The CONNECT request failed.
});

Real-world applications:

CONNECT requests are commonly used to establish secure connections to web servers. This is necessary for accessing secure websites, such as online banking sites or e-commerce websites.

CONNECT requests can also be used to establish secure connections to other types of servers, such as remote desktop servers or SSH servers.

ERR_HTTP2_ERROR

This error occurs when an unspecified issue happens during HTTP/2 communication. HTTP/2 is a protocol used for faster, more efficient communication between web servers and browsers.

ERR_HTTP2_GOAWAY_SESSION

This specific error occurs when the HTTP/2 connection is terminated unexpectedly by the server. The server may have closed the connection due to an issue or to free up resources.

Simplified Explanation

Imagine you're talking to a friend. You're sending messages back and forth, but suddenly, the connection is lost. You don't know why, but you can't reach your friend anymore. That's like the ERR_HTTP2_ERROR.

The ERR_HTTP2_GOAWAY_SESSION error is like when you're talking to your friend, and they suddenly hang up on you. You don't know why they did it, but you're not able to talk to them anymore.

Real-World Applications

These errors are typically encountered by developers while building or maintaining web applications that use HTTP/2.

Code Example

const fetch = require("node-fetch");

try {
  await fetch("https://example.com");
} catch (err) {
  if (err.code === "ERR_HTTP2_ERROR") {
    // Handle the error...
  } else if (err.code === "ERR_HTTP2_GOAWAY_SESSION") {
    // Handle the error...
  } else {
    // Handle other errors...
  }
}

Potential Applications

Website Development: Ensuring that HTTP/2 communication is established and maintained properly.
Web Hosting: Monitoring and managing HTTP/2 connections to optimize performance and handle potential errors.
Network Monitoring: Detecting and troubleshooting issues with HTTP/2 communication.
Load Balancing: Optimizing traffic flow and handling HTTP/2 connections across multiple servers.

Topic: ERR_HTTP2_GOAWAY_SESSION

Explanation:

Imagine you are playing a game with a friend over the internet. You have a special connection, like a tunnel, to communicate with each other. This connection is called an HTTP/2 session.

Suddenly, your friend sends you a message saying, "I'm going away! Don't send me any more messages." This is like when you press the "Leave Game" button. Now, you can't send any more messages to your friend because the connection, or session, is closed.

In coding terms, ERR_HTTP2_GOAWAY_SESSION means you tried to send a message through an HTTP/2 session that has already been closed.

Real-World Example:

In the world of web servers, HTTP/2 is used to send data between websites and your web browser. If a website decides to close its connection, you might see this error when trying to visit that website again.

Potential Applications:

Used by web servers to manage connections with browsers.
Helps avoid sending data to clients that have already disconnected.

Improved Code Example:

try {
  // Attempt to send a message through the HTTP/2 session.
  http2Session.write(message);
} catch (error) {
  // Catch the error if the session is closed.
  if (error.code === "ERR_HTTP2_GOAWAY_SESSION") {
    console.error("The HTTP/2 session has been closed.");
  } else {
    console.error("An unexpected error occurred:", error);
  }
}

Error: ERR_HTTP2_HEADER_SINGLE_VALUE

Meaning: HTTP is a protocol used to transfer data over the internet. HTTP/2 is a newer version of the protocol. In HTTP/2, certain header fields are required to have only a single value. If multiple values are provided for such a field, this error occurs.

Example:

// This code will throw the `ERR_HTTP2_HEADER_SINGLE_VALUE` error
const headers = {
  'content-type': ['text/html', 'application/json']
};

const options = {
  headers
};

const req = http2.request(options);
req.end();

In the above example, the content-type header field is required to have only a single value. However, two values have been provided, which causes the error.

Real-World Applications:

HTTP is used to transfer data over the internet. It is used in web browsers to load web pages, in mobile apps to communicate with servers, and in many other applications.

Potential Solutions:

There are two ways to solve this error:

Remove the duplicate values from the header field.
Use a different header field that allows multiple values.

`ERR_HTTP2_HEADERS_AFTER_RESPOND`

Simplified Explanation:

Imagine you're having a conversation with someone using a special messenger (HTTP/2). After you say something (respond), you can't go back and add more words (headers) to what you said.

Explanation in Detail:

In HTTP/2, headers are like the introduction to a message. They tell the receiver what to expect in the rest of the message. Once you send the response (the main message), you can't add more headers because the receiver has already started processing the message.

Code Example:

Suppose you want to send an HTTP/2 response with a header called "name" and a value of "John".

const http2 = require("http2");

const server = http2.createServer();

server.on("request", (req, res) => {
  res.writeHead(200, {
    "Content-Type": "text/plain",
  });

  // The following line will throw an `ERR_HTTP2_HEADERS_AFTER_RESPOND` error because the response was already sent.
  res.setHeader("name", "John");

  res.end("Hello");
});

server.listen(8080);

Potential Applications:

HTTP/2 is used in various web and mobile applications to improve performance and reduce bandwidth usage. By enforcing the rule that headers must come before the response, it ensures that messages are transferred efficiently and without confusion.

`ERR_HTTP2_HEADERS_SENT`

This error occurs when you try to send more than one response header in an HTTP/2 response.

Simplified Explanation:

Imagine you're writing a letter to a friend. You can write the "From" address only once, otherwise it will create confusion. Similarly, in HTTP/2 responses, you can only send one set of headers, which include information like the content type and the status code.

Real-World Example

const http2 = require("http2");

const server = http2.createSecureServer({});

server.on("stream", (stream) => {
  // Send multiple response headers (incorrect)
  stream.respond({
    ":status": 200,
    "content-type": "text/plain",
  });
  stream.end("Hello World!");
});

server.listen(443);

This code will throw the ERR_HTTP2_HEADERS_SENT error because we are trying to send multiple response headers (':status' and 'content-type') in the same response.

Applications in Real World

HTTP/2 is widely used in web applications for its efficiency and speed. By eliminating unnecessary overhead and sending fewer headers, it helps improve page load times and overall performance.

Simplified Explanation of ERR_HTTP2_INFO_STATUS_NOT_ALLOWED

HTTP/2 Responses

HTTP/2 is a newer version of the HTTP protocol that is used to communicate between web browsers and servers. Unlike HTTP/1, HTTP/2 uses binary data instead of text to transfer data.

Informational HTTP Status Codes

HTTP status codes are used to indicate the result of a request. Informational status codes (those starting with "1") are used to provide information about the request, but they do not indicate success or failure.

ERR_HTTP2_INFO_STATUS_NOT_ALLOWED

In HTTP/2, informational status codes are not allowed as the response status code. This means that if a server tries to send an informational status code as the response status code, the browser will throw the ERR_HTTP2_INFO_STATUS_NOT_ALLOWED error.

Example

The following code shows an invalid HTTP/2 response that uses an informational status code:

HTTP/2 100 Continue

This response would cause the browser to throw the ERR_HTTP2_INFO_STATUS_NOT_ALLOWED error.

Potential Applications

The ERR_HTTP2_INFO_STATUS_NOT_ALLOWED error can help to improve the reliability and security of web applications by ensuring that servers are following the correct HTTP/2 protocol.

`ERR_HTTP2_INVALID_CONNECTION_HEADERS`

In a conversation between a computer and a website, there are specific words that are used to establish a connection. These are called "connection headers."

HTTP/1 is an older way of sending and receiving information over the internet. HTTP/2 is a newer way that is faster and more efficient.

HTTP/1 connection headers are not allowed to be used in HTTP/2 conversations. It's like trying to use old-fashioned words in a modern conversation. It just doesn't belong.

// Example 1:

// Server code:
const http2 = require('http2');
const server = http2.createSecureServer();
server.on('stream', (stream) => {
  stream.on('headers', (headers) => {
    if (headers[':authority']) {
      // This is an HTTP/1 connection header. It is not allowed in HTTP/2.
      stream.rstStream(http2.constants.NGHTTP2_ERROR_PROTOCOL_ERROR);
    }
  });
});

// Client code:
const https = require('https');
const client = https.request({
  method: 'GET',
  host: 'localhost',
  port: 443,
  path: '/',
  headers: {
    ':authority': 'localhost' // This is an HTTP/1 connection header.
  }
});
client.end();

// Output:
// Error: ERR_HTTP2_INVALID_CONNECTION_HEADERS

This example shows how a server can reject a client request that uses an HTTP/1 connection header.

// Example 2:

// Server code:
const http2 = require('http2');
const server = http2.createSecureServer();
server.on('stream', (stream) => {
  stream.respond({
    ':status': 200
  });
  stream.end('Hello world');
});

// Client code:
const https = require('https');
const client = https.request({
  method: 'GET',
  host: 'localhost',
  port: 443,
  path: '/',
  headers: {
    'connection': 'close' // This is an HTTP/1 connection header.
  }
});
client.end();

// Output:
// Hello world

This example shows how a client can use an HTTP/1 connection header in an HTTP/2 request. The server does not reject the request, but it does not send the connection header back in the response.

Potential applications in real world

HTTP/2 is used by many websites and applications to improve performance. By using HTTP/2, websites can load faster and more efficiently. This can lead to a better user experience and increased sales for businesses.

Error: ERR_HTTP2_INVALID_HEADER_VALUE

Explanation:

Imagine you're baking a cake and following a recipe that says, "Add 1 cup of sugar." But instead, you accidentally add 1 cup of salt. The result will be a very salty cake!

Similarly, in HTTP/2, there are specific rules for the values of HTTP headers. If you send a header with an invalid value, it's like adding salt to a cake recipe. The server will get confused and reject the request, resulting in this error.

Simplified example:

// Sending an invalid header value
const headers = {
  'content-type': 'application/json',
  'custom-header': 'I'm not a valid value!'
};

fetch('https://example.com', { headers }); // Will throw the error

Real-world application:

HTTP headers are used in all types of web requests and responses. Ensuring that they have valid values is crucial for smooth communication between client and server.

Potential applications:

Validating headers in web browsers to prevent malicious requests
Enforcing strict header formats in web services for security and reliability

ERR_HTTP2_INVALID_INFO_STATUS

Simplified Explanation:

When using HTTP/2, you can send special codes called "informational status codes" to indicate that something is happening but the request is still in progress. These codes should be between 100 and 199. If you try to use a code that's not in this range, you'll get this error.

Real-World Example:

Imagine you're ordering pizza online. The website might send you an informational code of 102 to let you know that the order has been received but is not yet ready. If you sent an invalid code like 500, which is a server error, you'd get this error and the order might not be placed.

Complete Code Implementation:

try {
  // Send an invalid informational status code
  res.writeHead(201, {}, "Hello World!");
} catch (err) {
  console.error(err); // Output: ERR_HTTP2_INVALID_INFO_STATUS
}

Potential Applications:

In web servers, to communicate the progress of long-running operations like file downloads.

ERR_HTTP2_INVALID_ORIGIN

Simplified Explanation:

HTTP/2 is a way that web browsers and servers talk to each other. When a browser wants to connect to a server, it sends a message with a special field called "ORIGIN". This ORIGIN field tells the server which website the browser is coming from.

If the ORIGIN field is not valid or is missing, the server will give an error called ERR_HTTP2_INVALID_ORIGIN. This means the server can't tell where the browser is coming from.

Complete Code Implementation:

const http2 = require("http2");

const server = http2.createServer();

server.on("error", (err) => {
  if (err.code === "ERR_HTTP2_INVALID_ORIGIN") {
    // Handle the error here
  }
});

server.listen(8080);

Real World Application:

This error can occur if you have a proxy server or firewall that is not configured correctly. It can also occur if you are using a browser with an invalid or malicious extension.

Additional Information:

For more details and possible solutions, refer to the following resources:

`ERR_HTTP2_INVALID_PACKED_SETTINGS_LENGTH`

Simplified Explanation:

When you use the http2.getUnpackedSettings() function to unpack HTTP/2 settings from a packed buffer, the input buffer must be exactly six bytes long. If it's any other length, this error will be thrown.

Detailed Explanation:

HTTP/2 settings are passed around as a packed buffer. To unpack these settings, you can use the http2.getUnpackedSettings() function. This function expects the input buffer to have a length that is a multiple of six. Each six-byte block in the buffer represents a single HTTP/2 setting.

If the input buffer's length is not a multiple of six, the function will not be able to properly unpack the settings, and this error will be thrown.

Code Snippet:

const http2 = require("http2");

// Create a packed settings buffer with a length that is not a multiple of six
const packedSettingsBuffer = Buffer.from([
  0x40, 0x01, 0x00, 0x00, 0x00, 0x00, 0x40, 0x02, 0x00, 0x00, 0x00, 0x00,
]);

// Attempt to unpack the settings
try {
  const unpackedSettings = http2.getUnpackedSettings(packedSettingsBuffer);
} catch (err) {
  console.error(err); // ERR_HTTP2_INVALID_PACKED_SETTINGS_LENGTH
}

Real-World Application:

HTTP/2 settings are used to configure various aspects of the HTTP/2 connection, such as the maximum number of concurrent streams and the maximum frame size. Proper unpacking of these settings is critical for establishing and maintaining a stable HTTP/2 connection.

ERR_HTTP2_INVALID_PSEUDOHEADER

Simplified Explanation:

Imagine HTTP/2 as a special language that web browsers and servers use to talk to each other. In this language, there are some special words, called pseudoheaders, that have a specific meaning. You can't just make up any pseudoheader you want.

Topics in Detail:

What is a pseudoheader? A pseudoheader is a special keyword that appears in HTTP messages. They convey information about the message itself, such as the status code or the request method.
Valid pseudoheaders: There are only five valid pseudoheaders in HTTP/2:
- :status - The HTTP status code (e.g., 200 OK)
- :path - The path of the requested resource
- :authority - The host and port of the server
- :scheme - The protocol being used (e.g., HTTP or HTTPS)
- :method - The HTTP request method (e.g., GET or POST)
Error cause: This error occurs when you try to use a pseudoheader that is not one of the five valid ones.

Code Example:

// Invalid pseudoheader "My-Pseudoheader"
const headers = { ":My-Pseudoheader": "invalid" };

Real-World Applications:

Web servers: HTTP/2 is used by web servers to serve web pages and APIs. By using valid pseudoheaders, servers can communicate information about the HTTP message efficiently and securely.
Web browsers: HTTP/2 is used by web browsers to request web pages and resources. By using valid pseudoheaders, browsers can ensure that they receive the correct information from the server.

`ERR_HTTP2_INVALID_SESSION` Explained

Imagine you have a toy train set that you've been playing with all day. You've built a cool track and everything is running smoothly.

Suddenly, you decide you want to add a new train to the set. But when you try to connect it, you realize that the train isn't there! It's like it disappeared into thin air.

This is similar to what happens with ERR_HTTP2_INVALID_SESSION. It's an error that occurs when you try to use an Http2Session object that has already been "destroyed" or removed.

In the train example, the train is like the Http2Session object. When you try to add a new train (perform an action), but the train is gone (destroyed), you'll get an error like ERR_HTTP2_INVALID_SESSION.

Real-world example:

Let's say you're building a website and you're using Node.js to set up an Http2Session object. You use this object to handle communication between your server and clients.

If you accidentally destroy the Http2Session object (maybe by calling the close() method), any further actions you try to perform on it will result in ERR_HTTP2_INVALID_SESSION.

How to fix it:

To fix this error, make sure that you don't destroy the Http2Session object until you're absolutely sure you're done with it. And if you're not sure, double-check before you call the close() method.

Code Example

Here's a simplified example of how you can use an Http2Session object:

const http2 = require("http2");

// Create an HTTP/2 session object
const session = http2.connect(url);

// Listen for incoming data
session.on("data", (data) => {
  console.log(`Received data: ${data}`);
});

// Send data to the server
session.write("Hello from Node.js!");

// Close the session when done
session.close();

In this example, we create an Http2Session object using the http2.connect() method. We then listen for incoming data and send data to the server. Finally, we close the session using the close() method.

If you try to perform any actions on the session object after it has been closed, you will get an ERR_HTTP2_INVALID_SESSION error.

What is ERR_HTTP2_INVALID_SETTING_VALUE?

ERR_HTTP2_INVALID_SETTING_VALUE is an error that occurs when an HTTP/2 request or response contains an invalid setting. HTTP/2 settings are used to control the behavior of HTTP/2 connections, such as the maximum frame size and the initial window size.

What causes ERR_HTTP2_INVALID_SETTING_VALUE?

ERR_HTTP2_INVALID_SETTING_VALUE can be caused by a number of things, including:

A setting value that is outside of the allowed range
A setting value that is not supported by the server or client
A setting value that is not properly encoded

How to fix ERR_HTTP2_INVALID_SETTING_VALUE?

To fix ERR_HTTP2_INVALID_SETTING_VALUE, you need to identify the invalid setting value and correct it. This may involve checking the documentation for the HTTP/2 server or client that you are using, or using a tool such as Wireshark to inspect the HTTP/2 traffic.

Real-world example

One potential application of ERR_HTTP2_INVALID_SETTING_VALUE is in the development of HTTP/2 clients and servers. By using ERR_HTTP2_INVALID_SETTING_VALUE to handle errors related to invalid setting values, developers can ensure that their applications are robust and handle errors gracefully.

Simplified explanation

Imagine you are playing a game with a friend. The game has a rule that says you can only move your piece a certain number of spaces. If you try to move your piece more spaces than allowed, your friend will tell you that you can't do that because it's an invalid move.

ERR_HTTP2_INVALID_SETTING_VALUE is like your friend telling you that you can't make a move because it's invalid. It's a way for the HTTP/2 server or client to tell you that you can't use a certain setting value because it's not allowed.

Improved code snippet

The following code snippet shows how to handle ERR_HTTP2_INVALID_SETTING_VALUE in a Node.js application:

const http2 = require("http2");

const server = http2.createServer();

server.on("error", (err) => {
  if (err.code === "ERR_HTTP2_INVALID_SETTING_VALUE") {
    // Handle the error
  }
});

`ERR_HTTP2_INVALID_STREAM`

This error happens when you try to do something with a stream that has already been closed.

Simplified Explanation:

Imagine you have a water pipe. If you turn off the water, you can't turn it back on and use it again. The same thing happens with streams: once you close them, you can't use them anymore.

Real World Example:

const http2 = require("http2");

// Create an HTTP/2 server
const server = http2.createServer();

// Create a request and response stream
const stream = server.request();

// Close the stream
stream.end();

// Trying to use the stream after closing it will throw an `ERR_HTTP2_INVALID_STREAM` error
stream.write("Hello, world!");

Simplified Explanation of `ERR_HTTP2_MAX_PENDING_SETTINGS_ACK`

Imagine you're sending a package to a friend.

You pack the package and give it to the mailman.
The mailman sends a message back to you saying, "I got it!"

In HTTP/2, when you send a SETTINGS frame (like a package), the other person (the client) needs to send a message back saying, "I got it and I changed my settings."

But there's a limit to how many packages you can send without getting a message back. If you send too many packages, you'll get this error:

ERR_HTTP2_MAX_PENDING_SETTINGS_ACK

It means, "You've sent too many packages without getting a reply. Please wait for the client to respond before you send more."

Real-World Complete Code Implementation and Example

const http2 = require("http2");

const server = http2.createServer();

server.on("stream", (stream, headers) => {
  stream.respond();

  // Send too many SETTINGS frames without waiting for ACKs.
  for (let i = 0; i < 100; i++) {
    stream.pushStream({ settings: { maxConcurrentStreams: 1 } });
  }
});

server.listen(8000);

In this example, the server sends too many SETTINGS frames to the client without waiting for ACKs. This will cause the error ERR_HTTP2_MAX_PENDING_SETTINGS_ACK to be thrown by Node.js.

Potential Applications

Ensuring reliable communication by preventing overwhelming the receiver with unacknowledged SETTINGS frames.
Detecting and handling network issues or slow clients that may not be acknowledging SETTINGS frames promptly.

Simplified Explanation of ERR_HTTP2_NESTED_PUSH:

When you're building a website, you can send data to the browser using something called HTTP. Imagine it as a mailman delivering boxes to your house.

HTTP/2 is a newer version of HTTP that allows you to send multiple things at the same time, like multiple boxes in one trip.

But there's a rule: the mailman can only deliver boxes separately. He can't put a box inside another box and deliver it that way.

Similarly, in HTTP/2, you can't send data inside data. If you try to do this, you'll get the ERR_HTTP2_NESTED_PUSH error.

Code Example (simplified):

// Trying to send data inside data
const http2 = require('http2');

const server = http2.createSecureServer();

server.on('stream', (stream) => {
  stream.sendHeaders();

  // Incorrect - trying to send data inside data
  stream.pushStream({ ':path': '/nested-data' }, (error) => {
    if (error) {
      console.error('Error sending nested data:', error);
    }
  });
});

server.listen(8000);

In this example, we're trying to send data inside data, which is not allowed and will cause the ERR_HTTP2_NESTED_PUSH error.

Potential Applications:

HTTP/2 and push streaming can be useful for:

Faster page loading: It can send multiple resources (images, scripts, styles) at the same time.
Smoother video and audio streaming: It can ensure that data arrives in a consistent and timely manner.
Real-time communication: It can be used for building applications like chat and video conferencing.

`ERR_HTTP2_NO_MEM`

Cause:

This error occurs when there is not enough memory available to set the local window size for an HTTP/2 session. The local window size determines how much data can be sent from the HTTP/2 client to the server.

Simplified Explanation:

Imagine you are playing a game with a friend. The game board has a limited number of spaces where you can place your pieces. The local window size is like the number of spaces that you are allowed to occupy. If you try to place more pieces than you have spaces for, the game board will run out of memory and you will get an error.

Code Snippet:

The following code demonstrates how to set the local window size:

const { createServer } = require("http2");

const server = createServer();

server.on("stream", (stream, headers) => {
  // Set the local window size to 1000 bytes
  stream.setLocalWindowSize(1000);
});

server.listen(8000);

Real-World Applications:

Setting the local window size can help to optimize the performance of HTTP/2 connections by preventing the client from sending too much data at once. This can help to reduce latency and improve overall throughput.

Potential Applications:

Streaming video and audio content
Real-time messaging applications
Web applications that require a high level of interactivity

Simplified Explanation of ERR_HTTP2_NO_SOCKET_MANIPULATION

Imagine you have a special toy car that can only be used in a certain way. You can start it, turn it, and stop it, but you can't touch the wheels or open the hood.

In this case, the car represents an Http2Session object, and the wheels and hood represent the socket that it's connected to. The ERR_HTTP2_NO_SOCKET_MANIPULATION error happens when you try to do something to the socket directly, instead of using the Http2Session object to do it for you.

Code Snippets and Real-World Examples

Code Snippet:

const { Http2Session } = require("http2");

const session = new Http2Session();

// This will work because we're using the Http2Session object to do it
session.write("Hello world!");

// This will throw an error because we're trying to directly manipulate the socket
session.socket.write("Hello world!");

Real-World Example:

In a web server, Http2Session objects are used to handle HTTP/2 connections with clients. If a developer wants to send a response to a client, they should use the write() method of the Http2Session object, not the write() method of the underlying socket.

Potential Applications:

Debugging HTTP/2 connections
Implementing custom HTTP/2 servers and clients
Optimizing performance of HTTP/2 applications

`ERR_HTTP2_ORIGIN_LENGTH`

HTTP/2 ORIGIN frames are limited to a length of 16382 bytes. This error is thrown when an ORIGIN frame exceeds this length.

Simplified Explanation:

Imagine you're sending a postcard from one computer (client) to another computer (server). On the postcard, you're writing the website address (origin) where you want the server to fetch some data. But the postcard has a limited space to write, and you can't fit the entire origin address on it. That's when this error happens.

Potential Applications in Real World:

This error can occur in web applications where large amounts of data are being exchanged between the client and server. For example:

Streaming high-quality videos or music
Loading data-heavy web pages with lots of images or videos
Making complex API calls that return a lot of data

In these scenarios, it's important to ensure that the ORIGIN frame size is not exceeded to avoid this error.

`ERR_HTTP2_OUT_OF_STREAMS`

HTTP/2 is a protocol for sending data over the internet. It's like a special language that computers use to talk to each other.

With HTTP/2, you can send multiple streams of data at the same time, like sending a message and a picture at the same time. Each stream is like a separate conversation.

But there's a limit to how many streams you can have open at the same time. It's like having too many phone calls going on at the same time. If you try to open more streams than the limit, you'll get this error: ERR_HTTP2_OUT_OF_STREAMS.

Real-world example

Imagine you're trying to send a message and a picture to your friend. You can open two streams, one for the message and one for the picture. But if you try to open a third stream, you'll get the ERR_HTTP2_OUT_OF_STREAMS error.

Potential applications

HTTP/2 is used in many different applications, such as:

Web browsers: HTTP/2 makes web pages load faster.
Email clients: HTTP/2 makes it faster to send and receive emails.
File transfer programs: HTTP/2 makes it faster to download and upload files.

What is ERR_HTTP2_PAYLOAD_FORBIDDEN Error?

When you send a message over HTTP2 (a network protocol used for communication on the internet) and include some data (payload) with it, but the response code you're sending doesn't allow data to be included, you'll get this error.

Simplified Explanation:

Imagine you're writing a letter. You want to include a picture in the letter, so you write "I'm sending you a picture" at the top. But then you realize the letter is only supposed to have words, not pictures. This is similar to what happens when you get this error: you're trying to send data with a response code that doesn't allow it.

Real-World Example:

Let's say you have a website that lets people log in. When a user logs in successfully, you want to send back a response code of "200" (which means "OK"). But you also want to include a message like "Welcome back, [user's name]!" with the response. However, HTTP response code "200" doesn't allow any data to be included, so you would get this error.

Potential Applications:

Understanding this error can be useful in developing and debugging any application that uses HTTP2 for communication, such as web servers, web browsers, or mobile apps. It helps ensure that messages are correctly formatted and transmitted.

ERR_HTTP2_PING_CANCEL

Simplified explanation:

Imagine you're playing a game of tag with a friend. You send out a "ping" to your friend, asking them to tag you back. But before your friend can tag you, you decide to stop playing and cancel your ping.

The same thing happens with an HTTP/2 ping. It's like a way for two computers to check if they're still connected. But if one computer decides to stop waiting for a response, it cancels the ping.

Real-world example:

Let's say you're using a website that has a lot of pages. As you click on different pages, the website sends out pings to your computer to make sure you're still there and connected to the internet. But if you close the website early or your internet connection drops, the website will cancel the pings.

Potential applications:

Websites can use pings to keep track of active users.
Servers can use pings to detect and handle lost connections.

ERR_HTTP2_PING_LENGTH

When using HTTP/2, a communication protocol, you send "pings" to check if the connection is still active. These pings must be exactly 8 bytes long. If they're not, you'll get this error.

Simplified Example

Imagine a ping as a special message sent between two people to see if they can still hear each other. The message has to be exactly 8 "words" long, like "Hello, how are you?" If you send a message with more or less words, like "Hi!" or "Good morning, how are you today?", it won't work.

Real-World Applications

Web Browsers: Browsers use HTTP/2 to communicate with websites. If a user tries to open a website but the ping fails, they may not be able to load the page.
Online Games: Online games use HTTP/2 to send data between players. If the ping fails, players might experience lag or disconnections.

Potential Fixes

Check the length of your ping payload. Make sure it's exactly 8 bytes long.
Update your HTTP/2 library. Outdated libraries may not be able to handle pings correctly.
Contact your server administrator. They may be able to help troubleshoot the issue.

ERR_HTTP2_PSEUDOHEADER_NOT_ALLOWED

In HTTP/2, there are special header names that start with :, called pseudo-headers. These header names are reserved for specific purposes and should not be used for anything else.

For example, the :path pseudo-header is used to specify the path of the request. The :method pseudo-header is used to specify the HTTP method of the request.

If you try to use a pseudo-header name for a purpose other than its intended purpose, you will get the ERR_HTTP2_PSEUDOHEADER_NOT_ALLOWED error.

Here is an example of how to use a pseudo-header correctly:

const http2 = require('http2');

const server = http2.createServer();

server.on('stream', (stream) => {
  stream.respond({
    ':status': 200,
    'content-type': 'text/plain'
  });
  stream.end('Hello, world!');
});

server.listen(8000);

In this example, we are using the :status pseudo-header to specify the HTTP status code of the response. This is a valid use of a pseudo-header.

Here is an example of how to use a pseudo-header incorrectly:

const http2 = require('http2');

const server = http2.createServer();

server.on('stream', (stream) => {
  stream.respond({
    ':path': '/hello',
    'content-type': 'text/plain'
  });
  stream.end('Hello, world!');
});

server.listen(8000);

In this example, we are using the :path pseudo-header to specify the path of the request. This is not a valid use of a pseudo-header. The :path pseudo-header is reserved for specifying the path of the request, and it should not be used for anything else.

If you try to run this code, you will get the ERR_HTTP2_PSEUDOHEADER_NOT_ALLOWED error.

`ERR_HTTP2_PUSH_DISABLED`

Simplified Explanation:

Imagine you and your friend are playing a game where you take turns pushing each other on a swing. But your friend tells you not to push them anymore. If you try to push them anyway, the game will say "Push disabled!"

Technical Explanation:

In HTTP2, a protocol used for web communication, push streams allow a server to send data to a client even before the client requests it. However, if the client disables push streams, the server is not allowed to send any more. If the server tries to send a push stream anyway, the client will respond with this error.

Code Snippet:

try {
  // Send a push stream
  req.push("/");
} catch (err) {
  console.error(err); // { code: 'ERR_HTTP2_PUSH_DISABLED' }
}

Real-World Application:

Push streams are useful for preloading resources that a client might need in the near future, reducing page load times. However, some clients may disable push streams for security or privacy concerns.

`ERR_HTTP2_SEND_FILE`

Simplified Explanation:

Imagine you are trying to send a file to your friend, but your friend's computer doesn't understand how to receive it. The computer will say "File sending not allowed!"

Technical Explanation:

In HTTP2, the sendFile() method is used to send a file to a client. However, if a client does not support the SEND_FILE frame, the server will respond with this error.

Code Snippet:

try {
  // Send a file
  res.sendFile("/path/to/file.txt");
} catch (err) {
  console.error(err); // { code: 'ERR_HTTP2_SEND_FILE' }
}

Real-World Application:

sendFile() is a convenient way to serve static files, such as images and documents. However, some clients may not be able to handle large files or files that require special processing.

Error: HTTP2_SEND_FILE

This error occurs when you try to send a directory as a response using the Http2Stream.prototype.responseWithFile() method.

Why does this error occur?

When you want to send a file as a response, you need to specify the path to the file. If you specify a path to a directory, this error occurs because directories cannot be sent as responses.

How to fix this error?

To fix this error, you need to change the path to the file you want to send as a response to a path that points to a file.

Example

// Incorrect usage
const http2 = require('http2');
const fs = require('fs');

const server = http2.createServer();

server.on('stream', (stream) => {
  stream.respondWithFile('./directory');
});

server.listen(8080);

// Correct usage
const http2 = require('http2');
const fs = require('fs');

const server = http2.createServer();

server.on('stream', (stream) => {
  stream.respondWithFile('./file.txt');
});

server.listen(8080);

Potential applications in real world

This error can be encountered in any application that uses HTTP/2 and tries to send a directory as a response. For example, a web server that allows users to download files may encounter this error if a user tries to download a directory.

`ERR_HTTP2_SEND_FILE_NOSEEK`

When you use the Http2Stream.prototype.responseWithFile() function to send a file, you can't specify a starting point (offset) or a ending point (length) in the file.

Real-world example:

const http2 = require("http2");

const server = http2.createSecureServer();

server.on("stream", (stream, headers) => {
  stream.respondWithFile("big-file.txt");
});

server.listen(8000);

In this example, the server will send the entire contents of big-file.txt to the client. If you try to use stream.respondWithFile('big-file.txt', {offset: 100, length: 100}) to only send the first 100 bytes of the file, you will get the ERR_HTTP2_SEND_FILE_NOSEEK error.

Potential applications:

Sending files over HTTP/2 without having to load the entire file into memory.
Sending large files that are too large to fit in memory.
Sending files that are stored on a remote file system.

Simplified Explanation:

What is ERR_HTTP2_SESSION_ERROR?

Imagine you're playing a game of tag with your friends. You're all running around, and suddenly, the game stops. Everyone gets a message that says "Game Over." That's kind of like what happens with ERR_HTTP2_SESSION_ERROR.

What causes it?

This error happens when the game ends because someone closed the game window or did something wrong. In the case of HTTP2, it means that the connection between two computers that were talking to each other was broken in a bad way.

What does it look like in code?

The error message might look like this:

Error: ERR_HTTP2_SESSION_ERROR

How to fix it?

Unfortunately, there's not much you can do to fix this error on your own. It's usually caused by something wrong on the server side. You can try refreshing the page or checking your internet connection, but usually, you just have to wait for the server to fix the problem.

Real-world example:

Imagine you're trying to load a website, and you see this error message. It means that the website's server closed the connection for some reason. You can try refreshing the page, but it's likely that you'll have to wait until the server fixes the problem before you can load the website.

Potential applications:

This error can happen in any application that uses HTTP2, which is a way for computers to talk to each other on the internet. It's often used for websites, APIs, and other online services.

ERR_HTTP2_SETTINGS_CANCEL

Definition:

This error occurs when a server cancels the HTTP/2 settings during a communication with a client. HTTP/2 settings are used to configure the behavior of the HTTP/2 protocol, such as the maximum size of a data frame or the number of concurrent streams.

Explanation for a 5-Year-Old:

Imagine you and your friend are playing a game with rules. Suddenly, during the game, your friend changes the rules and says they want to play a different way. This unexpected rule change can cause confusion and makes it difficult to continue playing. Similarly, when a server cancels the HTTP/2 settings, it interrupts the communication and makes it hard for the client to know how to proceed.

Real-World Application:

HTTP/2 is used by many websites and applications for secure and efficient communication. If a server cancels the HTTP/2 settings during a communication, it can disrupt the website or application and result in an error message for the user.

Code Example:

try {
  // Make an HTTP/2 request
  const response = await https.get("https://example.com");

  // Process the response
} catch (error) {
  if (error.code === "ERR_HTTP2_SETTINGS_CANCEL") {
    // Handle the error
    console.error("HTTP/2 settings were canceled");
  } else {
    // Handle other errors
  }
}

Improved Code Example with Error Handling:

try {
  // Make an HTTP/2 request
  const response = await https.get("https://example.com");

  // Process the response
} catch (error) {
  switch (error.code) {
    case "ERR_HTTP2_SETTINGS_CANCEL":
      console.error("HTTP/2 settings were canceled");
      // Retry the request or take other appropriate action
      break;
    default:
      // Handle other errors
      console.error(`Error: ${error.message}`);
  }
}

ERR_HTTP2_SOCKET_BOUND

Simplified Explanation: Imagine you have a chair that can only hold one person. When you try to sit two people on the chair, one of them has to stand up and find another chair.

In this case, the chair is the HTTP/2 connection (like a room), the people are HTTP/2 sessions (like guests), and trying to put two people on the same chair is like trying to connect two HTTP/2 sessions to the same connection.

Detailed Explanation: An HTTP/2 connection can only handle one HTTP/2 session at a time. When you try to establish a second HTTP/2 session on the same connection, the first session has to "disconnect" and allow the second session to connect.

This error occurs when you try to connect a second HTTP/2 session to the same connection that is already being used by another HTTP/2 session.

Code Snippet:

const http2 = require("http2");
const net = require("net");

const server = http2.createServer();

server.on("stream", (stream) => {
  // Do something with the stream
});

const socket = net.connect(8080);

const session = http2.connect({ socket });

// This will fail with ERR_HTTP2_SOCKET_BOUND
const anotherSession = http2.connect({ socket });

Real World Application:

This error can occur in server applications that use HTTP/2 to handle multiple simultaneous connections from clients.

Potential Application:

A web server that uses HTTP/2 to provide faster page loading times and handle more concurrent requests.

Simplified Explanation of `ERR_HTTP2_SOCKET_UNBOUND`

What is it?

Imagine you have a special connection called an Http2Session that lets two computers talk to each other. To use this connection, you need a special "socket" that's like a plug.

If you try to use the socket after the connection has been closed, it's like trying to plug something into a wall outlet that has no electricity. The socket isn't connected to anything, so you can't use it.

Real-World Example

Think of it like a telephone call. When you hang up the phone, the call ends and the connection is broken. If you try to dial the same number again without reconnecting, you'll get a busy signal because the line is disconnected.

Potential Applications

ERR_HTTP2_SOCKET_UNBOUND is useful for error handling in applications that use the HTTP/2 protocol for communication. By catching this error, developers can gracefully handle situations where the connection has been closed and avoid unexpected behavior.

Simplified Explanation:

Error Code: ERR_HTTP2_STATUS_101

Meaning:

You cannot use the HTTP status code 101 (Informational) in HTTP/2.

Analogy:

Imagine you're playing a board game with your friends. You can't use a special move that's only allowed in a different game, because the rules are different. Similarly, HTTP/2 has different rules from other HTTP versions, and you can't use 101 there.

Real-World Example:

Let's say you have a website that uses HTTP/2 and you try to send a 101 status code to a user's browser. The browser will display an error message instead of showing your website's content.

Potential Applications:

Ensuring consistency and compatibility in HTTP/2-based applications.
Preventing confusion and errors when handling HTTP status codes.

Improved Code Example:

// Instead of using `101`, use an appropriate alternative status code for HTTP/2.
res.statusCode = 200; // OK

ERR_HTTP2_STATUS_INVALID

Explanation: Imagine HTTP status codes as special numbers used to tell a web browser how to handle a request. These numbers must be between 100 and 599. If you try to use a number outside this range, you'll get this error.

Real-World Example: When you visit a website, the server sends your browser a status code that indicates if the page loaded successfully, has an error, or needs further action. If the status code is not between 100 and 599, your browser will show an error message.

Code Implementation:

try {
  // Set a valid HTTP status code
  res.status(200);
} catch (error) {
  // Handle the error, which would be 'ERR_HTTP2_STATUS_INVALID'
  console.error(error);
}

Potential Application: This error can be used to ensure that HTTP status codes are used correctly in web applications to avoid unexpected behavior or security vulnerabilities.

Simplified Explanation:

Imagine you're talking to someone on the phone, and you're both speaking at the same time. To make sure you don't miss anything, you want to slow down the other person so you can listen properly.

ERR_HTTP2_STREAM_ERROR

In Node.js, the ERR_HTTP2_STREAM_ERROR error occurs when you try to communicate with someone using the HTTP/2 protocol, and that person stops talking before you've had a chance to say anything.

Real-World Example:

Imagine you're a website that needs to get data from another website. You start talking to the other website through HTTP/2, but the other website suddenly stops responding before you've received all the data you need. This would cause the ERR_HTTP2_STREAM_ERROR error on your website.

Potential Applications:

This error can help you identify and handle situations where data transfer is interrupted unexpectedly. For example, you could use the error to retry the data transfer or send an alert to users.

Simplified Explanation of ERR_HTTP2_STREAM_ERROR:

Imagine you're playing a game with two teams, and you need to pass a ball between players. Each player is a "stream" in the game.

Sometimes, when you pass the ball, something goes wrong, and the player who receives it sends a message back saying "Oops, I can't handle this ball!" This message is called an RST_STREAM frame.

Inside this message, there's a number called an "error code." The error code tells you why the player couldn't handle the ball. One of these error codes is ERR_HTTP2_STREAM_ERROR.

This error code means that there was a problem with the way the ball was being passed between players. For example, maybe the players were trying to pass the ball in the wrong order or from the wrong players.

Real-World Code Example:

const http2 = require('http2');

const server = http2.createSecureServer(...);

server.on('stream', (stream, headers) => {
  stream.on('RST_STREAM', (error) => {
    // Check if the error code is `ERR_HTTP2_STREAM_ERROR`
    if (error.code === 'ERR_HTTP2_STREAM_ERROR') {
      // Handle the error
    }
  });
});

server.listen(8443);

Potential Applications:

This error can occur in web servers that use HTTP/2 protocol. By handling this error properly, servers can ensure that data is passed correctly between clients and servers, providing a smooth and reliable user experience.

`ERR_HTTP2_STREAM_SELF_DEPENDENCY`

When you're using HTTP/2, you can set the priority for each stream. This means you can tell the server which streams are more important and should be processed first.

One stream can be a dependency of another stream. This means that the second stream can't be processed until the first stream is finished.

This error occurs when you try to make a stream a dependency of itself. This is like trying to make a circle: it doesn't make sense.

Real-world example:

Imagine you have a website with a lot of images. You want to make sure that the images are loaded quickly, so you set the priority for the image streams to be high.

However, you also want to load the HTML content of the page quickly, so you try to make the HTML stream a dependency of the image streams.

This would cause an error because you're trying to make the HTML stream a dependency of itself.

How to fix it:

Don't make a stream a dependency of itself.

HTTP2 Protocol Custom Settings Error

Problem: Your code is trying to send too many custom settings in an HTTP2 request.

What is HTTP2?

HTTP2 is an upgraded version of the HTTP protocol that makes websites faster and more secure.

What are Custom Settings?

Custom settings are optional parameters that can be used to adjust the behavior of an HTTP2 connection.

How Many Custom Settings are Allowed?

HTTP2 allows a maximum of 10 supported custom settings per connection.

Example of How to Set a Custom Setting

const { settings } = http2;

const customSettings = {
  "headerTableSize": 4096,
  "maxConcurrentStreams": 100,
};

const client = http2.connect('https://example.com', { settings: customSettings });

What Happens if I Set Too Many Custom Settings?

If you try to set more than 10 custom settings, you will get the ERR_HTTP2_TOO_MANY_CUSTOM_SETTINGS error.

How to Fix the Error

To fix the error, reduce the number of custom settings that you are sending.

Real-World Application

Custom settings can be used to optimize the performance of an HTTP2 connection depending on the specific server and client requirements. For example, increasing the header table size can reduce the number of times headers need to be sent, which can improve performance.

`ERR_HTTP2_TOO_MANY_INVALID_FRAMES`

Explanation:

This error occurs when a program receives too many invalid HTTP/2 protocol frames from another program. HTTP/2 is a protocol for exchanging web data between a client (like a web browser) and a server (like a website). The maxSessionInvalidFrames option specifies how many invalid frames are allowed before the server closes the connection.

Simplified Explanation:

Imagine HTTP/2 protocol frames as the messages that two programs send each other. If one program sends too many messages that don't follow the proper rules (like sending a message with the wrong format), the other program will stop listening to it.

Real-World Example:

A web server might set maxSessionInvalidFrames to 10. If it receives 10 invalid frames from a client, it will close the connection to prevent the client from sending more invalid frames and slowing down the server.

Code Example:

// Create an HTTP/2 server with a max invalid frames limit of 10
const http2 = require("http2");
const server = http2.createSecureServer({
  // ... other options
  maxSessionInvalidFrames: 10,
});

Potential Applications:

Preventing malicious clients from abusing servers by sending invalid frames.
Maintaining the stability and efficiency of web applications by ensuring that programs follow the HTTP/2 protocol correctly.

`ERR_HTTP2_TRAILERS_ALREADY_SENT`

Simplified Explanation:

You've already sent the trailing headers for this HTTP/2 stream. You can only send trailing headers once.

In-Depth Explanation:

In HTTP/2, trailing headers are a special type of header that can be sent after the response body has been sent. They are used to provide additional information about the response, such as the size of the response body or the presence of any attachments.

The ERR_HTTP2_TRAILERS_ALREADY_SENT error is thrown when you try to send trailing headers on an HTTP/2 stream that has already had its trailing headers sent. This is not allowed, as it would violate the HTTP/2 protocol.

Real-World Example:

You are developing a web server that uses HTTP/2. You want to send a response to a client that includes trailing headers. You accidentally send the trailing headers twice, which results in the ERR_HTTP2_TRAILERS_ALREADY_SENT error being thrown.

Potential Applications:

Trailing headers are used in a variety of applications, including:

Content negotiation: Trailing headers can be used to indicate the type of content that is being sent. This can help the client to determine how to process the response.
Error handling: Trailing headers can be used to provide additional information about an error that has occurred. This can help the client to understand the cause of the error and take appropriate action.
Logging: Trailing headers can be used to log information about the response. This information can be used to track the performance of the server and identify any potential problems.

Simplified Explanation:

Problem:

You tried to send "trailers" (additional information) in an HTTP/2 stream before it was ready to receive them.

Solution:

Wait for the 'wantTrailers' event to be emitted on the stream before sending trailers.

Detailed Explanation:

HTTP/2 Streams and Trailers:

HTTP/2 streams are like communication channels between two computers. In HTTP/2, data is sent in "frames," which can include trailers. Trailers are extra information that is sent after the main data.

waitForTrailers Option:

When you create an HTTP/2 stream, you can specify the waitForTrailers option. If you set this option to true, the stream will wait for a 'wantTrailers' event before it is ready to receive trailers.

Error Message:

If you try to send trailers before the 'wantTrailers' event is emitted, you will get the ERR_HTTP2_TRAILERS_NOT_READY error. This means that the stream is not yet ready to accept trailers.

Real-World Use Case:

Trailers are often used in HTTP/2 to send data that is not known until after the main data has been sent. For example, a web server might send trailers to include the total size of a file after it has been fully downloaded.

By using the waitForTrailers option, you can ensure that trailers are only sent when the receiving end is ready to process them. This helps prevent errors and ensures that communication is efficient.

Code Example:

const { createServer } = require("http2");

const server = createServer();

server.on("stream", (stream) => {
  // Set waitForTrailers to true
  stream.waitForTrailers = true;

  // Wait for 'wantTrailers' event before sending trailers
  stream.on("wantTrailers", () => {
    stream.sendTrailers({
      "x-total-size": "1024",
    });
  });

  stream.on("data", (chunk) => {
    // Process data...
  });
});

server.listen(443);

HTTP Errors in Node.js

When you make a request to a web server using the HTTP protocol, the server can respond with an error code. These error codes indicate that something went wrong with the request, and they can help you debug your code.

`ERR_HTTP2_UNSUPPORTED_PROTOCOL`

This error occurs when you try to connect to a web server using the HTTP/2 protocol, but the server does not support HTTP/2. HTTP/2 is a newer version of the HTTP protocol that is faster and more efficient than HTTP/1.1. However, not all web servers support HTTP/2 yet.

If you see this error, it means that you are trying to connect to a web server that does not support HTTP/2. You can try connecting to the server using HTTP/1.1 instead.

Real-World Example

Here is a real-world example of how you might encounter this error:

const http2 = require("http2");

const client = http2.connect("https://example.com");

client.on("error", (err) => {
  if (err.code === "ERR_HTTP2_UNSUPPORTED_PROTOCOL") {
    // The server does not support HTTP/2. Try connecting using HTTP/1.1 instead.
  }
});

In this example, we are trying to connect to the example.com web server using HTTP/2. However, if the example.com web server does not support HTTP/2, we will see the ERR_HTTP2_UNSUPPORTED_PROTOCOL error.

Potential Applications

This error can be helpful in debugging your code when you are trying to connect to a web server that does not support HTTP/2. By catching this error, you can avoid potential problems and connect to the server using HTTP/1.1 instead.

`ERR_ILLEGAL_CONSTRUCTOR`

This error occurs when you try to create an object of a class using a constructor that is not public. In other words, you're trying to use a "secret" way to create an object that the class doesn't allow.

Let's imagine a class called Animal that has a public constructor Animal(name). This constructor allows you to create an animal object with a specific name. However, let's say the class also has a secret constructor called Animal(secret). This constructor is not meant to be used by anyone outside the class.

If you try to use the Animal(secret) constructor outside the class, you'll get the ERR_ILLEGAL_CONSTRUCTOR error. This is because the class doesn't want you to create objects using that constructor.

Here's an example:

class Animal {
  constructor(name) {
    this.name = name;
  }

  // Secret constructor
  constructor(secret) {
    throw new Error("This constructor is secret!");
  }
}

const animal = new Animal("Fluffy"); // This will work

const animal2 = new Animal("secret"); // This will throw ERR_ILLEGAL_CONSTRUCTOR

Potential applications in real world

This error can be used to prevent unauthorized access to certain parts of a program. For example, if you have a class that contains sensitive information, you can use a private constructor to prevent other parts of the program from accessing it.

Simplified Explanation of `ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE`

The ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE error occurs when you try to import a module using the type attribute, but the module you're importing is actually a different type.

Imagine you're in a bookstore trying to buy a book. You ask the cashier to bring you a book of type "Fiction," but they accidentally bring you a book of type "Non-Fiction." That's what happens when you get this error.

Code Snippet

import { something } from "./some-module.js" type="module";

In the above example, you're trying to import something from the "some-module.js" module. But you're also specifying that the module is of type "module." However, the actual "some-module.js" module might be of type "commonjs." This will cause the ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE error.

Real-World Applications

This error is commonly encountered when you're working with Node.js modules. Modules in Node.js can be either of type "module" or "commonjs." Most modern modules are of type "module," but some older modules are still of type "commonjs."

When you're using a module bundler like webpack or Rollup, you need to specify the type of each module you're importing. If you get this error, it means that you've specified the wrong type for a module.

Conclusion

The ERR_IMPORT_ATTRIBUTE_TYPE_INCOMPATIBLE error is a relatively simple error to fix. Just make sure that you're specifying the correct type for each module you're importing. If you're not sure what the module type is, you can usually check the module's documentation or package.json file.

`ERR_IMPORT_ATTRIBUTE_MISSING`

This error occurs when you try to import a module that does not have a required attribute.

Simplified Explanation:

Imagine you have a box of building blocks. Each block has a different shape. To build a house, you need specific blocks, like squares and triangles. If you don't have all the blocks you need, you can't build the house.

In Node.js, modules are like building blocks. Each module has certain "attributes" that are like the shapes of the blocks. To use a module, you need all of its required attributes. If you try to use a module without all of its attributes, you'll get this error.

Real-World Example:

Imagine you have a module that helps you create a website. This module has an attribute called "createPage." To use this module, you need to have the "createPage" attribute. If you try to use the module without the "createPage" attribute, you'll get this error.

Potential Applications:

Checking if a module has all the required attributes before using it.
Debugging missing attributes in imported modules.

Code Example:

try {
  const moduleWithoutAttribute = require("./module-without-attribute");
} catch (err) {
  if (err.code === "ERR_IMPORT_ATTRIBUTE_MISSING") {
    // Handle the error
  }
}

ERR_IMPORT_ATTRIBUTE_UNSUPPORTED

This error occurs when you try to use an import attribute that is not supported in the version of Node.js you're using.

Example:

// This will throw an ERR_IMPORT_ATTRIBUTE_UNSUPPORTED error
import { foo } from "./module.js" assert { type: "module" };

Explanation:

In this example, we're trying to use the assert attribute, which is not supported in Node.js versions prior to 16.0.0.

Real-World Application:

This error can occur if you're using a newer version of Node.js to run code that was written for an older version. In this case, you'll need to update your code to use import attributes that are supported in your version of Node.js.

Improved Code Example:

// This code will run without errors
import { foo } from "./module.js";

Error: Incompatible Option Pair

This error means that you're trying to use two options at the same time that can't be used together.

For example:

// Trying to use both `maxmind` and `ipinfo` options at the same time.
const geoip = require("geoip-lite");
geoip.lookup("8.8.8.8", { maxmind: true, ipinfo: true }); // Error: Incompatible Option Pair

In this example, you can't use both the maxmind and ipinfo options because they do the same thing - lookup IP addresses.

Potential Applications:

Verifying that options are compatible before using them.
Ensuring that user input is valid and compatible with the available options.

ERROR OCCURED

`ERR_INPUT_TYPE_NOT_ALLOWED`

Stability: 1 - Experimental

The --input-type flag was used to attempt to execute a file. This flag can only be used with input via --eval, --print, or STDIN.

Can you please simplify and explain the given content from nodejs's errors module?

explain each topic in detail and simplified manner (simplify in very plain english like explaining to a 5 year old child).
retain code snippets or provide if you have better and improved versions or examples.
give real world complete code implementations and examples for each.
provide potential applications in real world for each.
ignore version changes, changelogs, contributions, extra unnecessary content.
```
  The response was blocked.
```

`ERR_INSPECTOR_ALREADY_ACTIVATED`

Imagine you have a secret code that allows you to see inside your computer's secrets. You can activate this code to let someone else see inside too. But if you've already activated the code, you can't activate it again. You need to turn it off first and then you can turn it on again at a different door (on a different port).

This error occurs when you try to activate the secret code when it's already activated.

Here's a simplified example:

const inspector = require("node:inspector");

// Activate the secret code
inspector.open();

// Try to activate it again
inspector.open(); // Error: ERR_INSPECTOR_ALREADY_ACTIVATED

Real-world Applications

This error can occur when you're trying to debug your code with a remote debugging tool like Chrome DevTools. If you get this error, it means you need to close the debugging tool and then start it again.

`ERR_INSPECTOR_ALREADY_CONNECTED`

Simplified Explanation:

Imagine that you're playing a game and have already started a video call with your friend to chat while playing. If you try to start another video call with the same friend, it won't work because you're already connected. Similarly, when using the node:inspector module, if you try to connect to the inspector when it's already connected, you'll get this error.

Real World Example:

This error can occur when using debugging tools, such as Chrome DevTools, with Node.js applications. If you try to connect to the inspector multiple times, you may encounter this error.

Code Example:

// Attempt to connect to the inspector multiple times
const inspector = require("node:inspector");

inspector.connect(); // First connection (successful)
inspector.connect(); // Second connection (fails with error)

// Expected output:
// {
//   name: 'ERR_INSPECTOR_ALREADY_CONNECTED',
//   message: 'Inspector is already connected.',
// }

Potential Applications:

Debugging Node.js applications remotely using tools like Chrome DevTools
Inspecting application state and performance metrics

`ERR_INSPECTOR_CLOSED`

Imagine you have a secret decoder ring and a friend who has the matching ring. You can write secret messages and your friend can decode them using their ring.

However, if your friend loses their ring, they can't decode your messages anymore. Similarly, with node:inspector, if the connection between the inspector and the Node.js process is closed, you can't use the inspector anymore to debug your code.

Real-World Example:

You're using the node:inspector module to debug a web application. While debugging, your browser window with the inspector panel accidentally closes. Now, you can't use the inspector to continue debugging because the connection is closed. You'll need to restart the Node.js process to establish a new connection and resume debugging.

Potential Applications:

Debugging Node.js applications remotely.
Profiling Node.js applications for performance issues.

ERR_INSPECTOR_COMMAND

This error occurs when you try to use the Node.js inspector module to execute a command, but the inspector is not active. The inspector is a tool that allows you to debug your code remotely.

How to fix it:

To fix this error, you need to start the inspector before you can execute commands. You can do this by running the following command:

node --inspect

The inspector will start and wait for a connection from a debugging tool.
The inspector is active when you see a message like this:

Debugger listening on ws://127.0.0.1:9229/1020c018-9936-4d97-81c1-0a4f5c894e5f

You can use this URL to connect to the inspector from a debugging tool, such as Chrome DevTools.

What is ERR_INSPECTOR_NOT_ACTIVE?

It's a Node.js error that happens when you try to use the inspector.waitForDebugger() function, but the debugger is not running in your Node.js process.

Why might this happen?

You might forget to start the debugger before calling inspector.waitForDebugger().

Simplified Explanation:

It's like you have a genie who can help you debug your code. But if you haven't summoned the genie first, and you try to ask it for help, it will say, "Hey, I'm not here!"

Real-World Example:

Imagine you're building a website. If you want to debug a problem, you might use the debugger to step through your code line by line and see what's going wrong. However, if you forget to start the debugger before you run your website, you'll get the ERR_INSPECTOR_NOT_ACTIVE error.

Improved Code Snippet:

try {
  await inspector.waitForDebugger();
} catch (error) {
  if (error.code === 'ERR_INSPECTOR_NOT_ACTIVE') {
    console.log('The debugger is not running. Start it first.');
  } else {
    throw error;
  }
}

Application:

The inspector module can help you debug your Node.js code and find bugs.

`ERR_INSPECTOR_NOT_AVAILABLE`

Simplified Explanation:

When you're debugging your code, you sometimes want to look inside the values of your variables. This error means that the tool you're using to do that, called the "inspector," is not turned on.

`ERR_INSPECTOR_NOT_CONNECTED`

Simplified Explanation:

This is a similar error to the one above. It means that the inspector is turned on, but it's not connected to the tool you're using to debug your code.

Real-World Examples

Let's say you're trying to debug a program that's not working correctly. You want to see the values of the variables inside the program, so you open up the inspector.

If you get the ERR_INSPECTOR_NOT_AVAILABLE error, it means that the inspector is not turned on. You need to turn it on before you can use it.

If you get the ERR_INSPECTOR_NOT_CONNECTED error, it means that the inspector is turned on but it's not connected to your debugging tool. You need to connect the inspector to your debugging tool before you can use it.

Potential Applications

The inspector is a powerful tool that can help you to debug your code more effectively. It can be used to:

Inspect the values of variables
See the call stack
Profile your code
Set breakpoints

Example Code

// Turn on the inspector
inspector.open();

// Connect to the inspector
inspector.connect();

Simplified Explanation:

Imagine you have a toy car with a remote control. You try to drive the car with the remote, but the car doesn't move because the remote isn't connected to it. Like that, when you use the node:inspector module, you need to first connect it to your program before you can use it. If you try to use it before it's connected, you'll get the ERR_INSPECTOR_NOT_CONNECTED error.

Real-World Example:

Let's say you have a Node.js program that you want to debug. You can use the node:inspector module to connect a debugger to your program and step through the code to find problems. However, if you don't connect the debugger before trying to use it, you'll get the ERR_INSPECTOR_NOT_CONNECTED error.

Code Implementation:

// Connect the inspector before using it
const inspector = require("node:inspector");
inspector.open(9229, "localhost", false);

// Now you can use the inspector to debug your program

Potential Applications:

Debugging Node.js programs
Profiling Node.js programs to identify performance issues
Testing Node.js programs

What is ERR_INSPECTOR_NOT_WORKER?

Imagine you have two people, the main thread and the worker thread, who are working together on a task. The main thread is the boss, and the worker thread is the assistant.

The main thread can ask the worker thread to do certain things, like calculate a number or fetch some data from the internet. But there are some things that the main thread can't ask the worker thread to do, like change the color of the boss's hair.

ERR_INSPECTOR_NOT_WORKER is an error that happens when the main thread tries to ask the worker thread to do something that it can't do.

Example:

const { Worker } = require("worker_threads");

const worker = new Worker("worker.js");

worker.on("message", (message) => {
  console.log(message);
});

worker.postMessage("Change my hair color to blue");

This code will throw the ERR_INSPECTOR_NOT_WORKER error because the main thread is trying to ask the worker thread to change its hair color, which is something that the worker thread can't do.

Potential Applications:

ERR_INSPECTOR_NOT_WORKER is used to prevent the main thread from asking the worker thread to do things that it can't do. This helps to ensure that the two threads are working together in a safe and efficient way.

ERR_INTERNAL_ASSERTION

Simplified Explanation:

1. What is it?

This error means there is a problem inside Node.js itself. It's like when a computer has a bug and can't work properly.

2. How to fix it?

You can't fix this error yourself. You should report it to the people who make Node.js so they can fix it. You can find them at this website.

Complete Code Implementation:

This is just an example to show where this error might appear:

function calculateSomething() {
  // There is a bug in this function that causes an internal assertion failure
  // ...
}

calculateSomething(); // This will throw the ERR_INTERNAL_ASSERTION error

Real-World Applications:

This error is not encountered by users directly. It's only seen by developers who are working with Node.js internally.

What is ERR_INVALID_ADDRESS_FAMILY?

It's like your computer is speaking a language you don't understand. Your computer uses different "address families" to talk to the internet, like IPv4 and IPv6. If you give your computer an address family it doesn't understand, it will say "I don't know what you're saying!" and give you this error.

Example:

// Try to connect to a website using an invalid address family
const net = require("net");

const socket = new net.Socket({
  addressFamily: "IPv9", // This is not a valid address family
});

socket.connect(80, "www.google.com");

This code will throw the ERR_INVALID_ADDRESS_FAMILY error because IPv9 is not a valid address family.

Real-World Application:

This error can be helpful when you're building programs that need to communicate over the internet. It ensures that your program uses the correct address family for the communication channel you're using.

Improved Example:

// Use a valid address family for IPv4
const socket = new net.Socket({
  addressFamily: "IPv4",
});

socket.connect(80, "www.google.com");

This code will connect successfully because it uses a valid address family.

Error Handling in Node.js

What is Error Handling?

When your program encounters a problem, it can throw an error. Error handling allows you to gracefully handle these errors, preventing your program from crashing.

Types of Errors

Node.js has several built-in error types:

ERR_INVALID_ARG_TYPE: Occurs when you pass a parameter of the wrong type.
ERR_INVALID_ARG_VALUE: Occurs when you pass a parameter with an invalid value.

Handling Errors

To handle errors, you can use the try...catch statement. The try block contains the code that may throw an error. The catch block contains the code that will handle the error if it occurs.

try {
  // Code that may throw an error
} catch (error) {
  // Code to handle the error
}

Example: Handling ERR_INVALID_ARG_TYPE

try {
  const name = 123; // Passing a number instead of a string
  console.log(name);
} catch (error) {
  if (error.code === "ERR_INVALID_ARG_TYPE") {
    console.log("The name must be a string.");
  } else {
    console.error(error);
  }
}

Example: Handling ERR_INVALID_ARG_VALUE

try {
  const age = -10; // Passing a negative number for age
  console.log(age);
} catch (error) {
  if (error.code === "ERR_INVALID_ARG_VALUE") {
    console.log("The age must be a positive number.");
  } else {
    console.error(error);
  }
}

Real-World Applications

Error handling is crucial in real-world applications to:

Prevent crashes: Errors can occur unexpectedly, causing the program to crash. Error handling allows you to catch these errors and keep the program running.
Provide meaningful feedback: When an error occurs, providing clear and specific error messages helps users understand the problem and take appropriate action.
Log errors for debugging: Errors can be logged to a file or database for later analysis. This helps developers troubleshoot and identify common issues.

`ERR_INVALID_ARG_VALUE`

Simplified Explanation:

You gave the function something it doesn't like. It's like giving a dog a banana. The dog doesn't want to eat it!

Detailed Explanation:

This error happens when you pass a value to a function that the function doesn't know how to handle. For example, if you try to give a function a string when it expects a number.

// This code will throw an ERR_INVALID_ARG_VALUE error.
const add = (a, b) => a + b;
add("1", "2");

Real-World Example:

Imagine you have a function that takes a person's age as an argument and tells you how long they've been alive. But instead of giving the function a number, you give it a person's name. The function won't know what to do with the name, so it will throw an error.

// This code will throw an ERR_INVALID_ARG_VALUE error.
const getAge = (age) => `You've been alive for ${age} years`;
getAge("John");

Potential Applications:

This error can be used to prevent functions from receiving invalid inputs. It helps ensure that functions work properly and don't produce unexpected results.

`ERR_INVALID_ASYNC_ID`

Simplified Explanation:

Imagine you're playing a game and you have a special number called an "async ID" that you use to track who is taking their turn. If you accidentally use the wrong number, the game gets confused and doesn't know whose turn it is.

In-Depth Explanation:

AsyncHooks is a Node.js feature that allows you to track asynchronous operations, which are actions that don't happen immediately. Each asynchronous operation has a unique async ID that identifies it.

If you use an invalid async ID when working with AsyncHooks, for example, by passing a number less than -1, Node.js will throw an ERR_INVALID_ASYNC_ID error. This error means that the async ID you provided is not valid, and Node.js cannot track the asynchronous operation.

Code Example:

const asyncHooks = require("async_hooks");

const hook = asyncHooks.createHook({
  // Example async hook implementation
});

hook.disable(); // Disable the async hook
hook.enable(); // Enable the async hook

const invalidAsyncId = -2;
hook.triggerAsyncId(invalidAsyncId); // Will throw an ERR_INVALID_ASYNC_ID error

Real-World Applications:

AsyncHooks is used to debug asynchronous code, profile performance, and track resource usage. It can be helpful in identifying and fixing issues with asynchronous operations that are causing slowdowns or errors in your application.

ERR_INVALID_BUFFER_SIZE

What it is: An error that is thrown when you try to change the size of a Buffer (a sequence of bytes) but the new size is not valid.
When it happens: This error happens when you try to change the size of a Buffer to a size that is smaller than the current size, or to a size that is not a multiple of the current size.
Example:

const buffer = Buffer.alloc(10); // Create a Buffer with 10 bytes

try {
  buffer.write("Hello"); // Write 'Hello' to the Buffer
} catch (err) {
  console.log(err.message); // Output: ERR_INVALID_BUFFER_SIZE
}

Real-world application: Buffers are used in many applications, such as reading and writing files, sending and receiving data over the network, and storing data in memory. If you try to change the size of a Buffer to a size that is not valid, this error will be thrown and your application will not be able to continue.

ERR_INVALID_CHAR

What it is: An error that is thrown when you try to use a character that is not valid in a particular context.
When it happens: This error happens when you try to use a character that is not allowed in a particular string, regular expression, or other context. For example, you cannot use a null character in a string because it is used to terminate the string.
Example:

const string = "Hello\0World"; // Try to use a null character in a string

try {
  console.log(string); // Output: ERR_INVALID_CHAR
} catch (err) {
  console.log(err.message); // Output: ERR_INVALID_CHAR
}

Real-world application: Strings are used in many applications, such as displaying text on a screen, storing data in a database, and sending and receiving data over the network. If you try to use a character that is not valid in a particular context, this error will be thrown and your application will not be able to continue.

What is ERR_INVALID_CHAR?

When you're sending messages over the internet, you use something called HTTP. HTTP has special rules about what characters you can use in the messages you send. ERR_INVALID_CHAR happens when you try to use a character that's not allowed in an HTTP message.

How to fix ERR_INVALID_CHAR?

You need to make sure that the characters you're using are allowed in HTTP messages. Here are the characters that are allowed:

Uppercase and lowercase letters (A-Z, a-z)
Numbers (0-9)
Special characters like hyphens (-), underscores (_), and periods (.)

Examples of ERR_INVALID_CHAR

Here are some examples of characters that are not allowed in HTTP messages and would cause ERR_INVALID_CHAR:

Spaces
Commas
Semicolons
Colons
Question marks
Ampersands

Applications of ERR_INVALID_CHAR

ERR_INVALID_CHAR is used in web development to make sure that messages sent over the internet are valid and can be understood by all devices.

ERR_INVALID_CURSOR_POS

This error occurs when you try to move a cursor on a stream to a specific row without specifying a column.

Simplified Explanation:

Imagine you have a table with rows and columns. You can only move the cursor to a specific spot in the table if you know both the row and column. If you only know the row, the cursor won't know where to go.

Code Snippet:

const readline = require("readline");

const rl = readline.createInterface({
  input: process.stdin,
  output: process.stdout,
});

// Try to move the cursor to row 5 without specifying a column
rl.cursorTo(5);

// This will throw an ERR_INVALID_CURSOR_POS error

Real-World Application:

This error can occur in any application that uses a stream, such as writing data to a file or displaying text on the screen.

Potential Applications:

Data logging
Text editors
Command-line interfaces
Database management systems

`ERR_INVALID_FD`

Simplified Explanation:

Imagine you have a magic box with 100 secret doors. Each door represents a file or resource that you can access on your computer. To open a door, you need a special key called a "file descriptor."

ERR_INVALID_FD means that you gave the wrong key. You tried to open a door with a key that doesn't fit, so the computer didn't know which file or resource you wanted to access.

Example:

const fs = require("fs");

try {
  // Try to open a file with an invalid file descriptor.
  fs.readFile(-1, (err, data) => {
    // The error will be `ERR_INVALID_FD`.
    console.error(err); // Output: Error: invalid file descriptor: -1
  });
} catch (err) {
  // Handle the error.
  console.error(err); // Output: Error: invalid file descriptor: -1
}

Real-World Application:

ERR_INVALID_FD can occur when:

You use a file descriptor that has been closed or is no longer valid.
You pass an invalid file path to a file operation.
You try to access a file that you don't have permission to access.

ERR_INVALID_FD_TYPE

In Node.js, files are represented by file descriptors. A file descriptor is a unique identifier that refers to an open file, such as a file on the hard disk or a network connection.

The ERR_INVALID_FD_TYPE error occurs when a function expects a file descriptor as an argument, but the argument passed is not a valid file descriptor.

Simplified Explanation:

Imagine that you have a box of toys. Each toy in the box has a unique number, called a "descriptor." The descriptor tells you what kind of toy it is (for example, "car" or "doll").

If you want to play with a toy, you need to know its descriptor. But if you try to use a descriptor that doesn't belong to any toy in the box, you'll get an error.

Real-World Example:

The following code tries to read data from a file descriptor:

const fs = require("fs");

try {
  const data = fs.readFileSync(1234); // <-- 1234 is not a valid file descriptor
} catch (err) {
  console.error(err); // <-- This will print "ERR_INVALID_FD_TYPE"
}

In this example, the readFileSync function expects a valid file descriptor as its first argument. However, the argument 1234 is not a valid file descriptor, so it throws the ERR_INVALID_FD_TYPE error.

Potential Applications:

Functions that deal with file descriptors, such as readFileSync, writeFileSync, and close, can throw the ERR_INVALID_FD_TYPE error if they receive an invalid file descriptor.

Simplified Explanation:

ERR_INVALID_FILE_URL_HOST happens when you use a file: URL with an unsupported host in Node.js. In other words, the "host" part of the URL (which usually contains the domain name) is not allowed.

Detailed Explanation:

1. File URLs

A file: URL is a special type of URL that points to a file on your computer. It looks something like this:

file:///Users/username/Documents/my-file.txt

2. Host

The "host" part of a URL is the domain name or IP address of the server hosting the file. In the example above, the host is empty ("").

3. Supported Hosts

On Unix-like systems (such as macOS, Linux, and Unix), only two hosts are supported for file: URLs:

localhost
Empty string (``)

4. ERR_INVALID_FILE_URL_HOST

If you try to use a file: URL with a different host (such as example.com), you will get the ERR_INVALID_FILE_URL_HOST error.

Example:

// This will work on Unix-like systems
const url = "file:///Users/username/Documents/my-file.txt";

// This will throw ERR_INVALID_FILE_URL_HOST on Unix-like systems
const url = "file://example.com/my-file.txt";

Potential Applications:

Reading and writing files from Node.js applications.
Using file: URLs to access local files from web browsers.
Sharing files across different devices and platforms.

Simplified Explanation:

Imagine you're trying to read a file from your computer using a special function in Node.js. But when you give the function the path to the file (like "C:\My Documents\myfile.txt"), it gives you an error called ERR_INVALID_FILE_URL_PATH.

This error means that the path you provided is not in the correct format for the function to understand. Different computers have different ways of organizing files, so the function needs to know the path in a specific way.

For example, on Windows, the path needs to be something like "file:///C:/My Documents/myfile.txt" (notice the extra slashes at the beginning).

Detailed Explanation:

File URL: A file URL is a special type of URL that points to a file on your computer, rather than a website on the internet. It looks something like this: file:///C:/My Documents/myfile.txt.
Path: The path is the part of the file URL that specifies the location of the file on your computer. In the example above, the path is "C:/My Documents/myfile.txt".
Platform-Dependent: The exact format of the path depends on the operating system (like Windows or macOS) that you're using.
Error: The ERR_INVALID_FILE_URL_PATH error occurs when the function tries to access a file using a path that is not in the correct format for the operating system.

Real-World Example:

You want to read a text file from your computer and store it in a variable. You use the fs.readFileSync() function in Node.js, which takes a file path as an argument. If you provide an invalid file path, you'll get the ERR_INVALID_FILE_URL_PATH error.

const fs = require("fs");

try {
  const data = fs.readFileSync("myfile.txt");
  console.log(data);
} catch (err) {
  if (err.code === "ERR_INVALID_FILE_URL_PATH") {
    console.error("Invalid file path.");
  } else {
    console.error(err);
  }
}

Potential Applications:

Functions that consume file URLs can be used in a variety of applications, such as:

Reading and writing files
Creating and deleting files
Copying and moving files
File system management tasks

ERR_INVALID_HANDLE_TYPE

Simple Explanation:

When you try to send a special type of object called a "handle" between two programs that are talking to each other (like a parent program and a child program), and the handle is not supported, you'll get this error.

Technical Details:

A handle is like a key that represents something else, like a file or a memory location. In Node.js, you can use handles to share resources between different programs. However, not all types of handles can be shared.

Real-World Example:

Imagine you have a parent program that wants to send a file to a child program. The parent program can create a handle for the file and then send it to the child program. The child program can then use the handle to access the file.

However, if the parent program tries to send a handle for a memory location instead of a file, the child program won't be able to use it and you'll get the ERR_INVALID_HANDLE_TYPE error.

Complete Code Example:

// Parent program

const { spawn } = require("child_process");

const child = spawn("node", ["child.js"]);

// Create a handle for a file
const fileHandle = fs.openSync("myfile.txt", "r");

// Send the file handle to the child process
child.send({ type: "fileHandle", handle: fileHandle });

// Child program

const { parentPort } = require("worker_threads");

parentPort.on("message", (message) => {
  if (message.type === "fileHandle") {
    // Use the file handle to access the file
    const fd = message.handle;
  }
});

Potential Applications:

Sharing files between programs
Sharing memory between programs
Creating custom communication protocols between programs

ERR_INVALID_HTTP_TOKEN

When trying to send a request to a server, if the request contains an invalid HTTP token, this error is thrown.

Real-world example:

Imagine you have a website where users can log in. When a user logs in, the server sends them a cookie. This cookie contains a token that the user's browser uses to identify them on subsequent requests. If the user's browser sends a request to the server with an invalid token, the server will respond with the ERR_INVALID_HTTP_TOKEN error.

Potential applications:

Ensuring that only authorized users can access certain resources on a website.
Detecting and preventing malicious requests from being sent to a server.

Simplified Explanation:

ERR_INVALID_IP_ADDRESS means that the computer is trying to connect to a device using an invalid IP address. An IP address is like a street address for devices on the internet. When the address is wrong, the computer can't find the device.

Real-World Code Implementation:

// Try to connect to a device using an invalid IP address
const net = require("net");
const socket = net.connect(
  {
    host: "127.0.0.1", // This is an invalid IP address
    port: 80,
  },
  () => {
    // The connection failed with the ERR_INVALID_IP_ADDRESS error
    console.error(socket.error); // Error: ERR_INVALID_IP_ADDRESS
  }
);

Potential Applications:

Verifying IP addresses in web forms or applications to ensure valid connections
Troubleshooting network connectivity issues and identifying incorrect IP configurations

ERR_INVALID_MIME_SYNTAX

Simplified Explanation:

Imagine you're sending a letter and you want to tell the post office what type of letter it is. You use different words for different types: "regular mail," "priority mail," "express mail." But if you make a mistake and write "prioritah meal," the post office won't know what to do with your letter.

In the same way, computers use MIME (Multipurpose Internet Mail Extensions) to tell each other what type of data they're sending. For example, they might say "text/html" for a web page or "image/jpeg" for a picture. But if you make a mistake and write "tehxt/html" or "imaje/jpeg," the computer won't be able to understand it. That's called "invalid MIME syntax."

Code Snippet:

try {
  // Send a request with an invalid MIME type
  const response = await fetch("https://example.com", {
    headers: { "Content-Type": "tex/html" },
  });
} catch (error) {
  if (error.name === "ERR_INVALID_MIME_SYNTAX") {
    // Handle the error
  }
}

Real-World Applications:

Valid MIME syntax is essential for computers to communicate properly. It's used in:

Sending emails
Uploading files to websites
Exchanging data between different programs

Simplified Explanation:

When you try to use a module in your code that doesn't exist or isn't formatted correctly, you'll get the ERR_INVALID_MODULE error.

Detailed Explanation:

Module Specifier

A module specifier is like the address of a module. It tells JavaScript where to find the module's code. A valid module specifier looks like this:

import { something } from 'some-module';

Common Invalid Module Errors

Typo: You mistyped the module name or path.
Non-existent module: The module you're trying to load doesn't exist.
Invalid module format: The module's code is not in a valid format, such as CommonJS or ES modules.

How to Fix It

Check the following:

Make sure the module name and path are spelled correctly.
Verify that the module actually exists.
Ensure that the module is in a valid format.

Real-World Example

Suppose you're writing a web page that uses a JavaScript library called "cool-library". If you mistype the library's name as "coll-library", you'll get an ERR_INVALID_MODULE error when you try to load it:

// This will cause an error because "coll-library" doesn't exist
import { coolFunction } from "coll-library";

Potential Applications

The ERR_INVALID_MODULE error can help you identify problems with your code by:

Letting you know that a module doesn't exist.
Informing you that a module is not formatted correctly.
Ensuring that you're loading modules from the correct locations.

Simplified Explanation:

ERR_INVALID_MODULE_SPECIFIER error means that the name of the module you're trying to import in your code is incorrect. It can't find the module with the name you've provided.

Real-World Example:

Imagine you have created a module called "myModule.js". To use this module in your code, you need to import it using the correct name:

import myModule from "myModule.js";

However, if you mistype the name as:

import myModule from "myModule.js"; // Incorrect: missing the '.js' extension

You'll get the ERR_INVALID_MODULE_SPECIFIER error because the JavaScript compiler expects the module name to include the file extension (.js).

Potential Applications:

This error can occur in any Node.js application that imports modules. Ensuring the correct module names are used is crucial for the smooth functioning of your application.

ERR_INVALID_OBJECT_DEFINE_PROPERTY

This error occurs when you try to set a property on an object that is not allowed or is not defined.

Simplified Explanation:

Imagine a box of toys. Each toy has a name, like "ball" or "car". You want to add a new toy to the box, but the box doesn't have a place for that toy. So, you get an error saying you can't add it.

Code Example:

// Object 'box' doesn't have a 'toy' property
const box = {};

// Try to set the 'toy' property to 'ball'
box.toy = "ball"; // Error: ERR_INVALID_OBJECT_DEFINE_PROPERTY

Real-World Applications:

Validating input data to ensure it meets expected formats
Protecting objects from unauthorized modifications
Providing consistent behavior for accessing and modifying object properties

Additional Notes:

The exact message of the error may vary depending on the context.
You can use Object.defineProperty() to define new properties on objects, or Object.freeze() to make an object immutable and prevent changes.

`ERR_INVALID_PACKAGE_CONFIG`

Plain language explanation:

When your computer tries to read the instructions for building your program (the package.json file), it finds a problem with the instructions and can't continue.

In-depth explanation:

The package.json file is a special file used by Node.js to tell the computer how to build and run your program. It contains information like the name of your program, the versions of the modules it depends on, and the scripts that need to be run to build and run your program.

If there's a problem with the package.json file, such as a typo or missing information, the computer won't be able to understand how to build your program and will throw an ERR_INVALID_PACKAGE_CONFIG error.

Real-world example:

Let's say you're building a program called "My Awesome App" and your package.json file looks like this:

{
  "name": "My Awesome App",
  "version": "1.0.0",
  "dependencies": {
    "express": "4.17.1",
    "body-parser": "1.19.0"
  },
  "scripts": {
    "start": "node index.js"
  }
}

However, you accidentally misspelled the name of one of the modules you depend on, and it should be "body-parser" instead of "bodyparser". In this case, the computer won't be able to find the module and will throw an ERR_INVALID_PACKAGE_CONFIG error.

Potential applications:

The ERR_INVALID_PACKAGE_CONFIG error is helpful for identifying problems with the configuration of your Node.js program. It can help you catch mistakes early on and prevent your program from failing during execution.

`ERR_INVALID_PACKAGE_TARGET`

Simplified Explanation:

Imagine your computer is a house and you have a room called "exports" in that house. This room stores instructions on how to find and use things outside the house (other files or modules).

If you try to find something outside the house using the instructions in the "exports" room, but the instructions are messed up or point to the wrong place, you'll get this error.

Technical Explanation:

The "exports" field in package.json specifies how to locate and import modules from the package. If the target specified in the "exports" field for a particular module is invalid or does not exist, this error occurs.

Code Snippet:

{
  "exports": {
    // Invalid target mapping
    "./module": "non-existent-file.js"
  }
}

Real-World Application:

This error can occur when:

You have a typo in the target path specified in the "exports" field.
The target file or module has been moved or renamed.
The target file or module is not accessible due to file permissions or other issues.

Potential Solutions:

Check for typos in the "exports" field target paths.
Verify that the target files or modules exist and are accessible.
Update the "exports" field to point to the correct locations.

`ERR_INVALID_PERFORMANCE_MARK`

In simple terms:

When you're measuring how long something takes with the Performance Timing API, you can mark specific points in time.

But if you try to mark a point in time that doesn't make sense, like before you started measuring or more than once, this error happens.

In technical detail:

Performance marks are used to track specific points in time during a performance measurement.
The ERR_INVALID_PERFORMANCE_MARK error is thrown when:
- A performance mark is given an invalid name.
- A performance mark is created before the performance measurement starts.
- A performance mark is created more than once with the same name.

Real-world example:

Imagine you're timing how long it takes to load a webpage. You can use a performance mark to track the time when the page starts loading and another mark to track the time when it finishes loading.

If you accidentally try to create a performance mark before the page starts loading, or if you try to create two performance marks with the same name, you'll get this error.

Code example:

// Start a performance measurement
performance.mark("start");

// Oops! Trying to create a mark before the measurement starts
performance.mark("too_early"); // ERR_INVALID_PERFORMANCE_MARK

// Create another mark with the same name as 'start'
performance.mark("start"); // ERR_INVALID_PERFORMANCE_MARK

Potential applications:

Performance monitoring: Measuring the speed and efficiency of websites, applications, and other software systems.
Debugging: Identifying performance bottlenecks and optimizing code.
User experience analysis: Understanding how users interact with a system and optimizing for usability.

`ERR_INVALID_PROTOCOL`

When you try to make a request to a web server using the http.request() function, you need to specify the protocol that you want to use. The most common protocols are http and https. If you specify an invalid protocol, you will get this error.

For example, the following code will give you the ERR_INVALID_PROTOCOL error:

const http = require("http");

const request = http.request({
  protocol: "ftp",
  host: "example.com",
  path: "/",
});

request.end();

To fix this error, you need to specify a valid protocol. For example, the following code will work:

const http = require("http");

const request = http.request({
  protocol: "http",
  host: "example.com",
  path: "/",
});

request.end();

Here is a real-world example of how this error can occur:

You are trying to access a website using the https protocol, but the website is only available over the http protocol.
You are trying to use a custom protocol that is not supported by the http.request() function.

Conclusion

The ERR_INVALID_PROTOCOL error is a simple error to fix. Just make sure that you are specifying a valid protocol when you make a request to a web server.

Potential Applications

The ERR_INVALID_PROTOCOL error can be used to:

Prevent users from accessing websites that are not available over the desired protocol.
Enforce the use of a specific protocol for security reasons.

`ERR_INVALID_REPL_EVAL_CONFIG`

When you try to set up a REPL (Read-Eval-Print-Loop) in Node.js, you can provide configuration options to customize its behavior. Two of these options are breakEvalOnSigint and eval.

breakEvalOnSigint: If set to true, it will interrupt the evaluation of the current expression if you press Ctrl+C (SIGINT). This can be useful if the expression is taking a long time to run and you want to stop it.

eval: If set to true, it will evaluate the expression using the eval() function. This can be useful if you want to execute JavaScript code that is dynamically generated or comes from an untrusted source.

However, you cannot set both breakEvalOnSigint and eval to true at the same time. This is because eval() can potentially execute arbitrary code, and if it were interrupted by Ctrl+C, it could leave the REPL in an unstable state.

Real-world example:

Let's say you are in a REPL session and you want to execute a long-running expression. You can set breakEvalOnSigint to true to make sure that you can interrupt the expression if necessary. However, if you need to execute JavaScript code from an untrusted source, you should set eval to true instead.

Simplified explanation for a 5-year-old child:

Imagine you are playing with a toy train. You can press a button to make it go, and another button to stop it. If you were to press both buttons at the same time, the train would not know what to do and it might get stuck. The same thing happens with the REPL options breakEvalOnSigint and eval. You cannot set both of them to true at the same time because it would confuse the REPL and make it behave strangely.

`ERR_INVALID_REPL_INPUT`

When you use the Node.js REPL (Read-Eval-Print-Loop) to interactively run JavaScript code, you may encounter the ERR_INVALID_REPL_INPUT error. This error occurs when you enter an invalid input that the REPL cannot process.

Simplified Explanation:

Imagine you're playing with a toy that lets you write letters and numbers. If you try to write something that's not a letter or number (like a smiley face), the toy might get confused and not know what to do. In the same way, the REPL can't handle certain types of input, like incomplete code or special characters.

Real-World Example:

> const x = 5;
> console.log(x

This code is incomplete and will result in the ERR_INVALID_REPL_INPUT error. You need to add the closing parenthesis to the console.log() statement.

> const x = 5;
> console.log(x);
5

Potential Applications:

The ERR_INVALID_REPL_INPUT error helps ensure that the REPL only runs valid JavaScript code, preventing errors and unexpected behavior.

`ERR_INVALID_RETURN_PROPERTY`

Simplified Explanation:

Imagine you're having a race with your friend. You both have toy cars, and before the race starts, you can change the wheels of your cars. You decide to use bigger wheels to make your car go faster.

After the race, you notice that your friend's car went much faster than yours. You ask him what kind of wheels he used, and he says, "I used blue wheels."

But that doesn't make sense because blue wheels are not a valid property for wheels. You can't actually change the color of wheels in real life. So you tell your friend that he's making up stuff, and that his answer is not a valid property of the wheels.

Code Example:

function getCarWheels() {
  return {
    color: "blue", // This is not a valid property for wheels
  };
}

try {
  const wheels = getCarWheels();
} catch (error) {
  console.error(error); // Will output "ERR_INVALID_RETURN_PROPERTY"
}

Potential Applications in the Real World:

Validating input data in web forms
Ensuring that data stored in a database is consistent and follows defined rules
Preventing errors in software programs

ERR_INVALID_RETURN_PROPERTY_VALUE

Simplified Explanation:

Imagine you have a magic box that you can ask to do things. When you ask it to do something, it gives you back an object with properties (like name, age, etc.). But sometimes, the magic box makes a mistake and gives you an object with a property that has the wrong type of value. That's when the magic box throws an "invalid return property value" error.

Detailed Explanation:

When you call a function in Node.js, you can pass it options as an object. These options have specific property names and expected value types. When the function executes, it returns an object with properties and values based on the options you provided.

However, if the function option does not provide the expected value type for one of its returned object properties, Node.js throws the ERR_INVALID_RETURN_PROPERTY_VALUE error. This means that the magic box didn't give you back the right kind of thing in the object it returned.

Code Snippet:

function getPersonInfo(options) {
  return {
    name: options.name, // Expected string
    age: options.age, // Expected number
    gender: options.gender // Expected string or undefined
  };
}

try {
  const personInfo = getPersonInfo({ name: 'John', age: 25, gender: 1 });
} catch (error) {
  console.error(error); // ERR_INVALID_RETURN_PROPERTY_VALUE: Expected string value for "gender"
}

In this example, the getPersonInfo function expects the gender option to be either a string or undefined. However, we passed in the number 1, which is not a valid value type. Hence, the ERR_INVALID_RETURN_PROPERTY_VALUE error is thrown.

Real-World Applications:

This error is important for ensuring that functions return objects with the correct format and data types. It helps prevent incorrect data from being used and potential bugs in your code. For example, if a database function is expecting a string as a parameter but receives a number, it could lead to incorrect query results or even data loss.

`ERR_INVALID_RETURN_VALUE` simplified

What is it?

It's an error that happens when a function doesn't return the type of value it's supposed to.

Example time!

Imagine a function called getAPromise is expected to return a promise (a special type of value in JavaScript). But instead, it returns a number.

function getAPromise() {
  return 42; // Oops! This should be a promise!
}

// Later on...

try {
  getAPromise();
} catch (error) {
  // The error is caught here and we can see that it's an `ERR_INVALID_RETURN_VALUE`.
  console.log(error.message); // Prints: "Cannot return a non-Promise value from a promise-returning async function"
}

Real-world applications

This error can help catch bugs in code that uses promises, ensuring that promises are handled correctly.

Example

A web server that handles user requests. If a request handler function returns a non-promise value, the server can catch the ERR_INVALID_RETURN_VALUE error and respond appropriately, such as by sending an error message to the client.

`ERR_INVALID_STATE`

Simplified Explanation:

ERR_INVALID_STATE means something is trying to do something it's not supposed to because it's not in the right condition or state.

Real-World Example:

Imagine you have a toy car that needs batteries. If you try to drive it without batteries, it won't work because it's not in the right state. It needs batteries to be able to drive.

Code Implementation:

const car = {
  hasBatteries: false,
  drive() {
    if (!this.hasBatteries) {
      throw new Error("ERR_INVALID_STATE: Car needs batteries to drive.");
    }
    // Drive the car...
  },
};

car.drive(); // Throws error because car doesn't have batteries.

Potential Applications:

ERR_INVALID_STATE can be used in various applications, such as:

Checking if an object has been destroyed before attempting to use it.
Ensuring that an operation is only performed when the conditions are right (e.g., checking if a file is open before trying to write to it).
Preventing users from performing certain actions if their account is not in the correct state (e.g., not allowing users to make purchases if their payment information is not up to date).

`ERR_INVALID_SYNC_FORK_INPUT`

Simplified Explanation:

Imagine you're playing on a particular part of a playground when your friend wants you to come play with him on a different part. If you just go without asking the teacher, you might get confused or make a mess. Similarly, in Node.js, if you try to send input to a new process without following the correct rules, you can end up with errors like ERR_INVALID_SYNC_FORK_INPUT.

Detailed Explanation:

In Node.js, we can create new processes ("forks") to run other code concurrently with the main program. To communicate with these processes, we can use standard input and output (stdio) streams.

When creating a fork, you have two options for handling stdio:

Asynchronous: This means that data is communicated non-blocking, i.e., it doesn't wait for the other end to be ready.
Synchronous: This means that data is communicated blocking, i.e., it waits for the other end to be ready.

The error ERR_INVALID_SYNC_FORK_INPUT occurs when you try to send input to an asynchronous fork using synchronous methods. This can happen if you provide a Buffer, TypedArray, DataView, or string as input.

Real-World Example:

Imagine you have a program that does some processing and wants to send results to another process. Here's an example using the correct way (asynchronous):

const { fork } = require("child_process");

const child = fork("child.js");

child.send("Hello from the parent!");

child.js:

process.on("message", (message) => {
  console.log(`Received from parent: ${message}`);
});

Potential Applications:

Sending commands to hardware devices or other processes.
Communicating between different parts of a distributed system.
Creating microservices that interact with each other.

`ERR_INVALID_THIS`

This error occurs when you call a Node.js method on an object that is not the expected type. Let's make it easier to understand with an example:

Example:

const urlSearchParams = new URLSearchParams("foo=bar&baz=new");

const buf = Buffer.alloc(1); // buffers are not URLSearchParams objects
urlSearchParams.has.call(buf, "foo");
// Throws a TypeError with code 'ERR_INVALID_THIS'

In this example, we have a URLSearchParams object called urlSearchParams and a Buffer object called buf. We are trying to call the has method on urlSearchParams with buf as the this value. This is not allowed because buf is not a URLSearchParams object.

Here's a simplified explanation of the error:

Who: ERR_INVALID_THIS occurs when you call a method on an object that is not the expected type.
What: The error message will tell you which method you tried to call and what type of object it expected.
Why: Node.js methods are designed to work on specific types of objects. Calling a method on the wrong type of object can lead to unexpected behavior or errors.
How to fix: Make sure you are calling the method on the correct type of object. You can check the documentation for the method to see what type of object it expects.

Here's a real-world example of how this error can occur:

Example:

const fs = require("fs");

fs.readFile("file.txt", function (err, data) {
  // Do something with the data
});

fs.readFile("file.txt", "utf8", function (err, data) {
  // This will throw an ERR_INVALID_THIS error
});

In this example, the first fs.readFile call is correct because it passes a callback function as the second argument. However, the second fs.readFile call is incorrect because it passes a string as the second argument. The fs.readFile method expects a callback function as the second argument, so this will throw an ERR_INVALID_THIS error.

To fix this error, you can update the second fs.readFile call to pass a callback function as the second argument:

fs.readFile("file.txt", "utf8", function (err, data) {
  // Do something with the data
});

`ERR_INVALID_TUPLE`

Simplified Explanation:

You're trying to create a URL that contains extra information, like a username and password or some search parameters. But the way you've entered this information is incorrect. It should be in a specific format, like this:

['username', 'John'],
['password', 'secret'],

Instead, you've provided information that doesn't match this format, like this:

['John', 'password'],

`ERR_INVALID_URI`

Simplified Explanation:

You're trying to provide a web address (URL) to a function, but the address you've entered is not valid. It could be missing parts, like the protocol (like https: or http:) or the domain name (like www.example.com).

Here's an example of a valid URL:

https://www.example.com/page.html

Here's an example of an invalid URL:

example.com

Real-World Implementations:

Example 1: ERR_INVALID_TUPLE

const searchParams = new URLSearchParams([["username", "John"]]);

In this example, the URLSearchParams constructor is trying to create a URL with a search parameter username set to John. However, the provided value is not in the correct tuple format, as it only has one element instead of two.

Example 2: ERR_INVALID_URI

const url = new URL("invalid-url");

In this example, the URL constructor is trying to create a URL object from the provided string, but the string is not a valid URL. It's missing the protocol and the domain name.

Potential Applications:

Web Development: When creating URLs for web pages or sending HTTP requests.
Data Validation: To ensure that data entered by users or from external sources is in the correct format.
Error Handling: To provide clear error messages when invalid input is encountered.

`ERR_INVALID_URI`

Explanation

When you try to access a resource (like a website or a file) using a URI (Uniform Resource Identifier), and the URI is not valid, you will get this error.

A URI is like an address that tells your computer how to find the resource you want to access. It usually starts with a protocol (like http or https), followed by a domain name (like www.example.com), and a path (like /index.html).

If the URI is missing any of these parts, or if any of these parts is not formatted correctly, the URI will be invalid.

Example

Here are some examples of invalid URIs:

http://example.com (missing the path)
https://www.example.com/index (missing the file extension)
file:///C:/Users/John/Desktop/index.html (using the wrong protocol)

Code Snippet

try {
  const url = new URL("http://example.com");
} catch (err) {
  console.error(err.message); // ERR_INVALID_URI
}

Real-World Applications

This error can be encountered in a variety of real-world applications, such as:

When you try to open a website in your browser
When you try to download a file from the internet
When you try to access a resource on a local network

Potential Solutions

To fix this error, you need to make sure that the URI you are using is valid. You can do this by:

Checking that the URI has all the necessary parts (protocol, domain name, path)
Checking that the URI is formatted correctly
Using a URI validation library

Additional Resources

`ERR_INVALID_URL` Error in Node.js

Explanation:

When you try to create a URL object in Node.js, you might run into the ERR_INVALID_URL error. This means that the URL you provided is not in the correct format.

Simplified Explanation:

Imagine you're building a website. You need to tell your computer where to find the pictures and text for the site. You give the computer an address, like "www.example.com/pictures/cat.jpg". But if you make a mistake in typing the address, the computer won't know where to find the picture. That's like getting the ERR_INVALID_URL error.

Code Snippet:

// Creating a URL object
const url = new URL("http://example.com");

// Trying to create a URL with an invalid format
const badUrl = new URL("not a valid url");

// Check if the URL is invalid
if (badUrl.toString() === "Invalid URL") {
  console.log("The URL is invalid");
}

Real-World Applications:

This error is important for ensuring that URLs are used correctly in applications:

Web browsers: To correctly load websites and display content.
Email clients: To handle email addresses and links.
Networking applications: To establish connections and exchange data.

Potential Applications:

Web development: Validating user input when they enter URLs in forms.
Data processing: Filtering out invalid URLs from a dataset.
Security: Detecting and blocking malicious URLs that could harm the system.

Simplified Explanation:

When you try to use a website address (URL) that starts with something other than 'file', you may get this error. It's like trying to use a key with a different shape for your house door.

Detailed Explanation:

URL Scheme: The first part of a URL (before the colon), such as 'http', 'https', or 'file', indicates the type of protocol or connection being used.
Incompatible Scheme: When trying to use a URL with an incompatible scheme (protocol), such as 'http'://example.com' in the Node.js 'fs' module, which only accepts URLs with 'file' scheme, you will encounter this error.

Example:

const fs = require("fs");

try {
  fs.readFile("http://example.com/file.txt"); // Will throw ERR_INVALID_URL_SCHEME
} catch (err) {
  console.error(err);
}

Applications:

Validating URLs with correct schemes for specific modules or APIs.
Preventing security vulnerabilities by restricting usage of incompatible schemes.

`ERR_IPC_CHANNEL_CLOSED`

Simplified explanation:

This error means that you tried to send a message through an IPC (Inter-Process Communication) channel that has already been closed. It's like trying to talk to someone on the phone after they have hung up.

In-depth explanation:

IPC is a way for different processes (running programs) to talk to each other. They use channels to send and receive messages. When a channel is closed, it means that one or both processes have stopped using it and it can't be used anymore.

Example:

const { ipcMain } = require("electron");

// Create an IPC channel
ipcMain.on("message", (event, arg) => {
  console.log(arg); // Print the message sent by the renderer process
});

// Close the IPC channel
ipcMain.removeListener("message");

// Now, if you try to send a message through this channel, you'll get the `ERR_IPC_CHANNEL_CLOSED` error
ipcMain.emit("message", "Hello"); // ERROR: ERR_IPC_CHANNEL_CLOSED

Real-world applications:

Electron: IPC channels are commonly used in Electron apps to communicate between the main process and renderer processes (web pages).
Node.js: The IPC module can be used for communication between different Node.js processes.

Potential solutions:

Check if the IPC channel is closed before trying to send messages.
If the channel is closed, recreate it and re-establish the communication.

Simplified Explanation:

ERR_IPC_DISCONNECTED:

When you have two programs that are talking to each other using a "pipe", which is like a virtual tube, and you try to disconnect the pipe when it's already disconnected, this error happens. It's like trying to unplug a phone charger that's already unplugged.

ERR_IPC_ONE_PIPE:

This error happens when you try to create multiple "pipes" between two programs, but each program should only have one. It's like trying to connect two different hoses to the same faucet.

Real-World Applications:

These errors are common when using the child_process module in Node.js to communicate between parent and child processes. One example is when you create a child process to execute a command and want to stop it using the disconnect() method.

Code Implementations:

// Example 1: Trying to disconnect an already disconnected IPC channel
const { spawn } = require("child_process");

const child = spawn("ls", []);

child.disconnect(); // This will throw ERR_IPC_DISCONNECTED

// Example 2: Trying to create multiple IPC pipes
const child = spawn("ls", [], { stdio: ["ignore", "pipe", "pipe"] });

child.on("error", (err) => {
  if (err.code === "ERR_IPC_ONE_PIPE") {
    // Handle the error
  }
});

Simplified Explanation:

Imagine you have a pipe, like a water hose. You can connect one end of the hose to a faucet and the other end to a sink. This allows water to flow from the faucet to the sink.

ERR_IPC_ONE_PIPE is an error that occurs when you try to connect more than one pipe to the same faucet. This means that the water cannot flow through the pipes properly.

Detailed Explanation:

In Node.js, the child_process module allows you to create new child processes that run independently of the main process. These child processes can communicate with the main process using pipes, which are like virtual hoses.

By default, child processes created using child_process have one pipe for standard input and one pipe for standard output. These pipes allow the main process to send data to the child process and receive data from it.

However, ERR_IPC_ONE_PIPE occurs when you try to create a child process with more than one pipe for either standard input or standard output. This is because the pipes are shared resources that cannot be used by multiple processes at the same time.

Code Snippet:

const childProcess = require("child_process");

// Create a child process with one pipe for standard input and one pipe for standard output
const child = childProcess.spawn("ls", ["-la"]);

// Try to create another pipe for standard input
childProcess.createPipe("stdin", child);

// This will throw **ERR_IPC_ONE_PIPE** because the child process already has one pipe for standard input

Real-World Applications:

ERR_IPC_ONE_PIPE is typically encountered when you try to use a third-party module or library that creates child processes with multiple pipes. In such cases, you may need to contact the developers of the module or library to find a workaround.

Potential Applications:

Pipes are commonly used for communication between different processes, such as:

Sending data from a database server to a web server
Forwarding logs from a child process to the main process
Controlling a child process from the main process

ERR_IPC_SYNC_FORK

Simplified Explanation:

You tried to talk to another Node.js process that was created at the same time as your current process. This isn't allowed, because both processes are like twins and can't communicate directly.

Detailed Explanation:

In Node.js, you can create new processes using the child_process module. By default, when you create a new process, it's like cloning the current process. They share the same memory and everything.

But sometimes, you might want to create a new process that's completely independent. To do this, you can use the fork() method instead. This creates a new process that has its own memory and everything.

The error ERR_IPC_SYNC_FORK happens when you try to create an IPC (Inter-Process Communication) channel between a parent process and a child process that was created using fork(). This is not allowed because the child process is completely independent and can't communicate directly with the parent process.

Code Example:

// This code will throw ERR_IPC_SYNC_FORK
const childProcess = require("child_process");

const child = childProcess.fork("some-script.js");

// Try to send a message to the child process
child.send("Hello, child!");

Real-World Applications:

Creating independent processes for specific tasks, such as running a web server or processing data.
Avoiding potential performance issues or security vulnerabilities that could arise from sharing memory between processes.

Note:

This error is not related to the child_process.exec() or child_process.spawn() methods.
To communicate between a parent process and a forked child process, you should use the IPC channel provided by the cluster module.

ERR_LOADER_CHAIN_INCOMPLETE

Explanation:

Imagine you have a chain of people standing in a line, passing a ball to each other. Each person is like an "ESM loader hook".

When a ball is passed to a person, they can do one of two things:

Pass the ball to the next person in line (calling next())
Stop the line and keep the ball (signaling a "short circuit")

Error Scenario:

In this error, one of the people in the line didn't do either of those things. They just held onto the ball without passing it on or stopping the line.

Real-World Analogy:

It's like when you're playing a game with your friends and it's your turn to do something. You could either pass the turn to your next friend or end the game. But instead, you just sit there, holding the ball and confusing everyone.

Applications in Real World:

This error can occur when using Node.js's "module" system to load code written in JavaScript's "ESM" (EcmaScript Modules) format.

Example Code:

// example.mjs (ESM code)
export const message = "Hello World!";

// loader.js (ESM loader hook)
export function load(url) {
  if (url === "example.mjs") {
    // This is where the error could occur
    // We forgot to call `next()` or signal a short circuit
    // Instead, we just do nothing and hold onto the ball
  }
}

In this example, the loader.js hook forgets to pass on the ball (call next()) or stop the line (signal a short circuit). This leaves the module loading process incomplete, resulting in the ERR_LOADER_CHAIN_INCOMPLETE error.

`ERR_MANIFEST_ASSERT_INTEGRITY`

What is it?

When you try to load a file from a website, the website can specify what the file should look like. If the file doesn't match what the website said it should look like, this error is thrown.

Example:

try {
  const response = await fetch('https://example.com/script.js');
  const text = await response.text();
  // This will throw an error because the script.js file doesn't match the
  // integrity specified by the website.
  eval(text);
} catch (error) {
  // Handle the error here.
}

Potential applications:

Websites can use integrity checks to make sure that the files they load are not corrupted or tampered with.
This helps to protect users from malicious attacks.

`ERR_MANIFEST_DEPENDENCY_MISSING`

Simplified Explanation:

When you load something (like a website or a game), it tells the computer what it needs to show it properly. If the computer is told it needs something but can't find it, it will show this error.

Real-World Example:

Imagine you want to play a game. The game says it needs a sound file called "music.wav". But when the computer goes to find "music.wav", it's not there. The computer will then show a message saying "ERR_MANIFEST_DEPENDENCY_MISSING: music.wav" because it's missing the thing it needs to play the game properly.

Applications in Real World:

Websites can use this to ensure that all the images and scripts they need are available.
Games can use this to make sure that all the graphics and sound effects they need are present.
Any application that loads resources from different locations can use this to ensure that everything is loaded correctly.

Error: Manifest Integrity Mismatch

Explanation:

When you use a policy manifest to manage your browser's policies, you need to make sure that the manifest has consistent entries for all the resources it covers. If there are multiple entries for a resource that don't match each other, your browser will throw this error.

Real-World Example:

Imagine you have a manifest that defines policies for two websites: www.example1.com and www.example2.com. If you have an entry for www.example1.com that allows pop-ups and another entry for the same website that blocks pop-ups, your browser will encounter this error because it doesn't know which policy to apply.

Solution:

To fix this error, you need to update the manifest to ensure that all the entries for each resource match each other. In our example, you would need to remove one of the entries for www.example1.com so that the manifest has a single consistent policy for that website.

Code Example:

// Example of a valid manifest entry
{
  "url": "https://www.example.com",
  "policies": {
    "cookies": "allow"
  }
}

// Example of an invalid manifest entry with multiple policies for the same resource
{
  "url": "https://www.example.com",
  "policies": {
    "cookies": "allow",
    "cookies": "block"
  }
}

`ERR_MANIFEST_INVALID_RESOURCE_FIELD`

Simplified explanation:

When telling the computer what to do with a certain resource (like a file or folder), there was a mistake in the instructions. The computer is unable to carry out the action because of this error.

Explanation in detail:

In Node.js, policy manifests are used to define how resources (such as files, folders, or network connections) should be handled by the application.
If a resource in a policy manifest has an invalid value for one of its fields, this error will occur.
To correct this error, update the manifest entry with the correct value.

Real-world example:

Consider you're creating a policy manifest to restrict access to a specific folder on your computer. The manifest contains an entry that grants access to users with the "manager" role. However, you accidentally entered "manager_" instead of "manager" as the role name.

When you try to apply the policy, you'll get the ERR_MANIFEST_INVALID_RESOURCE_FIELD error because the "manager_" role does not exist. To resolve the issue, you need to update the manifest entry to use the correct role name ("manager").

Potential applications:

Policy manifests are useful for managing access to resources in a secure and consistent way. They can be used in various applications, including:

File and folder permissions
Network access control
Database security
Cloud security

ERR_MANIFEST_INVALID_SPECIFIER

What is it?

This error occurs when a file called a "policy manifest" contains a mistake in how it lists other files that it depends on.

Imagine this:

You have a big puzzle with many pieces. You have a list that tells you which pieces you need to find to complete the puzzle. If the list has a mistake, you might not be able to find all the pieces and finish the puzzle.

How to fix it:

You need to check the policy manifest file and make sure that the list of dependencies is correct. If there's a mistake, update it to match the correct files.

Real-world example:

Let's say you have a website that shows news articles. The website uses a policy manifest to control who can see which articles. If the policy manifest has a mistake in the list of dependencies, users might not be able to see all the articles they should be able to.

Potential applications:

Controlling who can access different parts of a website or app
Managing security settings
Setting up rules for how data is stored and shared

ERR_MANIFEST_PARSE_POLICY

This error is thrown when Node.js tries to load a policy manifest (a file that defines security policies for a given JavaScript module), but it's unable to parse the manifest.

Simplified explanation:

Imagine you have a secret box that contains important information. You want to create a set of rules (a policy) to control who can open the box and what they can do with its contents. You write down these rules in a special book (the policy manifest). But when you try to open the book, it's all garbled and you can't understand it. That's like getting the ERR_MANIFEST_PARSE_POLICY error.

Real-world example:

Consider a company that wants to share sensitive data with external partners while protecting the data from unauthorized access. They can use a policy manifest to define who has access to the data and what they can do with it. If the policy manifest is not properly formatted or contains errors, Node.js will throw the ERR_MANIFEST_PARSE_POLICY error.

Code implementation:

try {
  // Load the policy manifest
  const manifest = require("./policy.json");

  // ... Use the policy manifest to enforce security ...
} catch (err) {
  if (err.code === "ERR_MANIFEST_PARSE_POLICY") {
    // Handle the error gracefully
    console.error(
      "Unable to parse the policy manifest. Please check the manifest format and ensure it is valid JSON."
    );
  } else {
    // Handle other errors
  }
}

Potential applications:

Policy manifests are used in various applications, including:

Access control and authorization systems
Data protection and privacy management
Digital rights management
Content filtering and moderation

ERR_MANIFEST_TDZ

Imagine you have a toy chest full of toys. You want to play with a specific toy, but you can't reach into the chest yet because the lid is still closed.

In the same way, when you use Node.js, there is a "policy manifest" that contains important information about how the program should run. When you try to use this information, it's like trying to reach into the toy chest before the lid is open. You get this error because the information is not yet available.

ERR_MANIFEST_UNKNOWN_ONERROR

This is a special case of the previous error. It means that Node.js doesn't know how to handle a specific error that occurred while trying to access the policy manifest. It's like the toy chest is locked and you don't know how to open it.

Real-World Applications

Policy manifests are important for managing security and permissions in Node.js applications. For example, they can be used to control who has access to certain files or data. By handling these errors properly, you can ensure that your applications are secure and reliable.

Code Example

// Example code that might throw ERR_MANIFEST_TDZ:

try {
  // Try to access the policy manifest before it's initialized
  console.log(policyManifest);
} catch (err) {
  if (err.code === "ERR_MANIFEST_TDZ") {
    // Handle the error by waiting for the manifest to initialize
  } else {
    // Handle the error by logging it or displaying it to the user
    console.error(err);
  }
}

Error: ERR_MANIFEST_UNKNOWN_ONERROR

Simplified Explanation:

When you load a policy for your website or application, there's a special rule that tells the website what to do if something goes wrong. But if that rule has a value that the website doesn't recognize, it will throw this error.

In-Depth Explanation:

A policy is like a set of instructions that guides how your website or application should behave. It can define rules for things like who can access the website, what data is allowed, and what to do if an error occurs.

One of the rules in a policy is called "onerror." It tells the website what to do if something unexpected happens. For example, it could direct the website to display a custom error message or redirect users to another page.

However, if the "onerror" rule has a value that the website doesn't understand, it won't know what to do and will throw this error.

Code Snippet:

// Loading a policy with an unknown onerror value
const policy = {
  onerror: "something-the-website-doesn't-understand",
};

try {
  // Attempting to use the policy
  // This will throw the ERR_MANIFEST_UNKNOWN_ONERROR error
  applyPolicy(policy);
} catch (error) {
  console.error("Error applying policy:", error);
}

Real-World Application:

Websites and applications need to handle errors gracefully, providing clear and useful feedback to users.
Policies can help define consistent and reliable error handling across different pages and applications.
By using a clear and well-defined "onerror" rule, websites can ensure users have a good experience even when things go wrong.

ERR_MEMORY_ALLOCATION_FAILED

Simplified Explanation:

When your computer tries to run a program and needs more memory, it tries to ask for it from the computer's memory storage. But sometimes, the computer doesn't have enough memory left to give to the program, and then the program can't run. It's like when you want to fill up a glass of water, but the glass is already full and you can't fit any more water in it.

Real World Example:

Imagine you have a game on your computer that you want to play. When you start the game, your computer needs to load the game into its memory so that it can run. But if your computer doesn't have enough memory left, the game won't be able to load and you won't be able to play it.

Potential Applications:

Memory-intensive programs, such as video games or video editing software
Opening too many programs or tabs at the same time
Running multiple virtual machines on a single computer
Heavy multitasking on mobile devices

ERR_MESSAGE_TARGET_CONTEXT_UNAVAILABLE

What is it?

When you send a message from one part of your program to another, sometimes those messages can't be understood. This is like trying to speak to someone in a different language.

Why does it happen?

Not everything in your program can be easily understood by other parts of your program. It's like trying to send a drawing to someone who doesn't know how to draw.

How do I fix it?

You can't always fix it, but you can try to send simpler messages or use different ways to send messages.

Real-world example:

Imagine you're building a game where you want the player to control a car on the screen. You could send messages to the car to tell it where to go. If the car doesn't understand the message, it won't move.

Code example:

// This message can't be understood by the car.
const message = {
  type: "unknown",
  data: [1, 2, 3],
};

// This message might be understood by the car.
const message = {
  type: "move",
  data: [10, 20],
};

Simplified Explanation of ERR_METHOD_NOT_IMPLEMENTED in Node.js

Sometimes, functions in code are like "recipes" that have to be followed to do something. If a function is required (necessary) to make the code work but isn't actually written out, it's like the recipe is missing a step or an ingredient. This missing step or ingredient would make the code not work.

Real-World Example:

Imagine you're baking a cake. The recipe calls for adding sugar, but you forget to write it in. When you try to bake the cake, it won't turn out right because you skipped a crucial step.

Potential Application in Real World:

In software development, functions are used to perform specific tasks. If a function is required to complete a task but isn't implemented, the software won't work as intended. For example, in a web application, a function that loads user data from a database may not be implemented, resulting in the page not displaying the user's information.

Here's a simplified code example:

function bakeCake() {
  // Missing step: add sugar
  mixIngredients();
  bake();
}

Code Implementation:

Throwing an ERR_METHOD_NOT_IMPLEMENTED error can be done like this:

throw new Error('Method not implemented');

Improved Example:

A better approach is to create a custom error class that extends the built-in Error class:

class MethodNotImplementedError extends Error {
  constructor() {
    super('Method not implemented');
  }
}

function bakeCake() {
  if (!hasSugar) {
    throw new MethodNotImplementedError();
  }

  mixIngredients();
  bake();
}

This approach provides more context and can be caught and handled specifically.

ERR_MISSING_ARGS

Imagine you're building a toy car, and you need to put in the wheels. But instead of putting in all four wheels, you only put in two. This is like when a function in your program needs some information to work properly, but you forget to provide it.

Real-World Example:

Let's say you're writing a function that calculates the area of a circle. The function takes two arguments: the radius and the mathematical constant pi. If you call the function without providing the radius, it will throw this error.

function calculateArea(radius, pi) {
  return pi * radius ** 2;
}

calculateArea(); // ERR_MISSING_ARGS: The radius argument is missing.

Potential Applications:

This error ensures that your program doesn't crash when it's missing essential information. It helps you catch problems early on and makes your code more reliable.

`ERR_MISSING_OPTION`

Simplified Explanation:

Imagine you're playing a game with a friend, and you need to give them a toy car to start playing. If you forget to give them the toy car, your friend won't be able to play the game. In the same way, when you're using a computer program (API), some features might need certain settings to work. If you forget to provide those settings, the program will give you this error message because it's missing an essential option.

Real-World Example:

Suppose you're using a library that allows you to connect to a database. To connect, you need to provide a username and password. If you forget to include the password, the library will throw this error because the password is a required option for connecting to the database.

Code Example:

// Code without the required password option:
const options = {
  username: "my_username",
};

// Try to connect to the database:
try {
  const connection = connectToDatabase(options);
} catch (err) {
  if (err.code === "ERR_MISSING_OPTION") {
    console.log("Missing required password option.");
  }
}

// Code with the required password option:
const options = {
  username: "my_username",
  password: "my_password",
};

// Try to connect to the database:
try {
  const connection = connectToDatabase(options);
} catch (err) {
  if (err.code === "ERR_MISSING_OPTION") {
    console.log("Missing required password option.");
  }
}

Potential Applications:

Ensuring that all necessary settings are provided before executing a task.
Debugging errors related to missing options in API calls or function configurations.
Preventing incorrect or incomplete execution of programs due to missing options.

`ERR_MISSING_PASSPHRASE`

What is it?

This error occurs when you are trying to read an encrypted key that requires a passphrase, but you forgot to provide it. It's like having a lock and key, but forgetting which key unlocks the lock.

How to fix it?

To fix it, simply provide the correct passphrase when you are decrypting the key.

Example:

// Import the Node.js crypto module
const crypto = require("crypto");

// Create an encrypted key
const encryptedKey = crypto
  .createCipher("aes-256-cbc", "myPassword")
  .update("mySecretMessage", "utf8")
  .finalize();

// Decrypt the key using the correct passphrase
const decryptedKey = crypto
  .createDecipher("aes-256-cbc", "myPassword")
  .update(encryptedKey, "base64")
  .finalize();

// Use the decrypted key to decipher the secret message
const secretMessage = crypto
  .createDecipher("aes-256-cbc", decryptedKey)
  .update("myEncryptedMessage", "base64")
  .finalize();

console.log(secretMessage.toString()); // "mySecretMessage"

Applications in the real world:

Protecting sensitive data stored in databases or cloud storage
Securing communication between applications
Encrypting sensitive user information

`ERR_MISSING_PLATFORM_FOR_WORKER`

Simplified Explanation:

You're trying to use a special feature in Node.js called "Workers" that allows your program to run tasks in the background. But this feature is not supported by the software (called the "platform") that Node.js is using.

Detailed Explanation:

Workers: Workers are special threads that you can create in your Node.js program to run tasks in parallel. This means that you can break up your program into smaller pieces and have them run at the same time, which can make your program faster.

Platforms: Node.js can run on different platforms, like Windows, macOS, and Linux. Each platform provides different features and capabilities. In this case, the platform that you're using doesn't support Workers.

Real-World Applications:

Workers are useful when you have tasks that take a long time to complete, such as processing large amounts of data or performing complex calculations. By using Workers, you can offload these tasks and keep your main program running smoothly.

Examples:

// This code will throw an ERR_MISSING_PLATFORM_FOR_WORKER error because Workers are not supported on this platform.
const worker = new Worker("./worker.js");

Potential Applications:

Processing large data files
Performing complex calculations
Running simulations
Creating games or animations

Simplified Err_Module_Not_Found

What is it?

Imagine you have a toy car race and each toy car is a module. When you want to start the race (run the program), the race organizer (ECMAScript modules loader) tries to find all the toy cars (modules) you need. But if the race organizer can't find one of the toy cars (modules) it needs, it throws an "ERR_MODULE_NOT_FOUND" error.

Example:

Let's say you want to start a race with 3 toy cars: Red Car, Blue Car, and Green Car. You tell the race organizer to find all 3 toy cars. But the race organizer can't find the Blue Car. It will say, "Oops, I can't find the Blue Car." And the race can't start.

Real-World Application:

When you build a website or app, you often use pieces of code called "modules." These modules are like building blocks that you put together to create the website or app. If you try to use a module that doesn't exist or can't be found, you'll get an "ERR_MODULE_NOT_FOUND" error.

`ERR_MULTIPLE_CALLBACK`

Imagine you're waiting for a friend to call you. You give them your phone number, and they say they'll call you back.

But then, your friend calls you twice! You're confused because you were only expecting one call. This is similar to what happens in Node.js when you call a callback function more than once.

A callback function is like a message that says, "Hey, I'm done with my task. Let me know what you want to do next."

In Node.js, you usually provide a callback function when you start an asynchronous task, like making a request to a server. When the task is done, the callback function is called with the result.

But if the callback function is called more than once, it can lead to unexpected behavior. For example, if the callback function updates a database, it might update the database multiple times, which can cause data corruption.

Real-world example

Imagine you're building a website that lets users sign up for an account. When a user clicks the "Sign up" button, you start an asynchronous task to create their account in the database.

You provide a callback function to the asynchronous task, which is called when the account is created. In the callback function, you send a confirmation email to the user.

If the callback function is called more than once, it might send multiple confirmation emails to the user, which can be annoying and confusing.

Improved code snippet

Here's an improved version of the code snippet in the documentation:

const mysql = require("mysql2");

const connection = mysql.createConnection({
  host: "localhost",
  user: "root",
  password: "password",
  database: "my_database",
});

connection.query("SELECT * FROM users", (err, rows) => {
  if (err) throw err;

  console.log("Query results:", rows);
});

In this example, the callback function is called only once, when the query is complete. If the callback function is called more than once, the err parameter will be set to an ERR_MULTIPLE_CALLBACK error.

ERR_NAPI_CONS_FUNCTION

When you tell a computer to build something using a plan called a constructor, but that plan is not actually a plan, your computer gets confused and throws a ERR_NAPI_CONS_FUNCTION error.

ERR_NAPI_INVALID_DATAVIEW_ARGS

When you try to look at part of your computer's memory using a tool called a DataView, but you don't tell it the right way to look, your computer doesn't understand what you want and throws a ERR_NAPI_INVALID_DATAVIEW_ARGS error.

Real-World Applications

ERR_NAPI_CONS_FUNCTION:

Writing a program to create objects based on a blueprint
Using a library that expects constructors to be functions

ERR_NAPI_INVALID_DATAVIEW_ARGS:

Reading data from a file or network using a DataView
Manipulating memory in a custom application

Example Code

ERR_NAPI_CONS_FUNCTION:

// Incorrect: constructor is not a function
const InvalidConstructor = 123;
const object = new InvalidConstructor();

// Correct: constructor is a function
const ValidConstructor = function () {};
const object = new ValidConstructor();

ERR_NAPI_INVALID_DATAVIEW_ARGS:

// Incorrect: invalid arguments to DataView constructor
const dataView = new DataView(buffer, offset, length, littleEndian);

// Correct: valid arguments to DataView constructor
const dataView = new DataView(buffer, 0, buffer.byteLength, true);

ERR_NAPI_INVALID_DATAVIEW_ARGS

When using the napi_create_dataview() function to create a new DataView object, the following error may be thrown:

ERR_NAPI_INVALID_DATAVIEW_ARGS

This error indicates that the specified offset value is outside the bounds of the buffer argument, or that the sum of offset and length is greater than the length of the buffer.

Simplified Explanation:

Imagine you have a book with 100 pages. You want to create a new view of the book, starting at page 15 and ending at page 25.

If you try to create a view that starts at page 10 or ends at page 30, you will encounter this error. You cannot start a view before the first page or end a view after the last page.

Code Snippet:

const buffer = Buffer.from("Hello World!");
try {
  const dataview = new DataView(buffer, 0, 15); // Create a view of the first 15 bytes
} catch (err) {
  console.error("Error:", err.message);
}

Output:

Error: ERR_NAPI_INVALID_DATAVIEW_ARGS

Potential Applications:

The DataView object provides a convenient way to access the underlying binary data of a buffer in a more structured way. It can be used to read and write various types of data, such as integers, floats, and strings.

One potential application is to parse binary data received from a network connection or a file. By using a DataView, you can easily access and decode the data without having to manually convert it to a more convenient format.

`ERR_NAPI_INVALID_TYPEDARRAY_ALIGNMENT`

Explanation

When creating a TypedArray using napi_create_typedarray(), the offset parameter must be a multiple of the element size. This error is thrown when that condition is not met.

Simplified

Imagine you have a box with 4 slots to store numbers. If you want to put a number in the second slot, you need to skip the first slot. However, if you try to put a number in the middle of the second slot (like 1.5), it won't fit because the box is not designed for that.

Code Snippet

const offset = 3; // Not a multiple of 4 (size of a Float32Array element)
const array = new Float32Array(10, offset);
// Throws ERR_NAPI_INVALID_TYPEDARRAY_ALIGNMENT

Real World Application

TypedArrays are used to store large amounts of data in a binary format. They are commonly used in graphics and audio applications.

Simplified explanation of ERR_NAPI_INVALID_TYPEDARRAY_LENGTH:

When you're creating a TypedArray (a special kind of array that stores data in a binary format), you need to specify the length of the array and the size of each element. If the length you specify is too long, the size of the array will be bigger than the buffer (a chunk of memory) you're using to store the data. This is like trying to fill a cup with more water than it can hold.

Code snippet:

const buffer = new ArrayBuffer(10); // Creates a buffer with 10 bytes
const typedArray = new Uint8Array(buffer, 0, 20); // Tries to create a typed array with 20 elements, but the buffer only has 10 bytes

Real-world example:

Imagine you want to store a list of numbers in memory. You create an array with a length of 10 and each element takes up 1 byte of memory. This means the array will take up 10 bytes. But if you try to access the 11th element, you'll get this error because the array only has 10 elements and there's no memory allocated for the 11th element.

Potential applications:

TypedArrays are used in various applications, including:

Image processing
Audio and video encoding
Data analysis

Improved code snippet:

To fix the error, you should ensure that the length of the TypedArray multiplied by the size of each element is less than or equal to the length of the buffer.

const buffer = new ArrayBuffer(10); // Creates a buffer with 10 bytes
const typedArray = new Uint8Array(buffer, 0, 5); // Creates a typed array with 5 elements, which fits within the 10-byte buffer

Error: `ERR_NAPI_TSFN_CALL_JS`

Simplified Explanation:

You tried to use a special type of JavaScript function (called a "thread-safe function") in a way that caused a problem.

Detailed Explanation:

Thread-safe functions are functions that are designed to be safe to use in multithreaded environments. This means that they can be called from multiple threads at the same time without causing any problems.

In this case, you tried to call a JavaScript thread-safe function, but there was a problem while calling the JavaScript part of it. This is a rare error and usually happens due to a bug in the underlying Node.js implementation.

Code Snippet:

const tsf = require('napi-tsfn');

const jsFunction = tsf.makeThreadSafeFunction((a, b) => {
  // Do something in JavaScript
});

jsFunction(1, 2); // This line might throw `ERR_NAPI_TSFN_CALL_JS`

Real-World Application:

Thread-safe functions are useful in situations where you need to perform operations from multiple threads at the same time without worrying about race conditions or other concurrency issues. For example, you might use them in server applications where you want to handle client requests concurrently.

Potential Applications:

Concurrent request handling
Multithreaded processing
Safe inter-thread communication

`ERR_NAPI_TSFN_GET_UNDEFINED`

Simplified Explanation:

Your code tried to get a special value in JavaScript called undefined, but something went wrong. Undefined is like a magic word that means there's nothing there.

`ERR_NAPI_TSFN_START_IDLE_LOOP`

Simplified Explanation:

Your code tried to start a loop that does nothing but wait for something to happen. This is usually used to check if anything important has happened while your code was busy doing other things. But for some reason, it didn't work.

What is ERR_NAPI_TSFN_START_IDLE_LOOP?

Imagine a busy playground where kids (data) are running around and playing (being processed). There's a special area (queue) where kids wait their turn to play.

But sometimes, the playground has a "silent time" where all the kids have to calm down and stop playing (idle loop). This error happens when there's a problem starting "silent time" on the playground.

How it works:

Kids (data) enter the queue to wait their turn to play (be processed).
When it's time for "silent time," the playground tries to start it.
If there's a problem starting "silent time," this error appears.

Example:

// Start idle loop on the main playground
try {
  playground.startIdleLoop();
} catch (err) {
  // Handle the error (ERR_NAPI_TSFN_START_IDLE_LOOP)
}

Real-world applications:

Keeping track of data that needs to be processed in an orderly manner.
Managing a queue of tasks that need to be completed in a certain order.
Handling data that is constantly being added and removed from a queue.

`ERR_NAPI_TSFN_STOP_IDLE_LOOP`

When you're using a Node.js add-on that uses the napi_tsfn_start_idle_loop function, you must also call napi_tsfn_stop_idle_loop when you're done with the loop. If you don't, you'll get this error.

Simplified explanation:

Imagine you're playing a game of tag with your friends. You start running around, trying to tag them, but after a while, everyone gets tired and stops running. You need to tell everyone to stop running or they'll keep running forever. This error is like when you forget to tell everyone to stop running and they keep going.

Real-world example:

const addon = require('./my-addon');

addon.startIdleLoop();

// Do some stuff

addon.stopIdleLoop();

`ERR_NOT_BUILDING_SNAPSHOT`

Imagine you're building a Lego house. You have two sets of Legos: one set to build the house and one set to decorate it.

If you try to use the decoration set before you finish building the house, you might get confused and not be able to build the house properly.

In the same way, Node.js has two modes: one for building the main program (the house) and one for adding extra features (the decorations).

If you try to use the decoration mode before the main program is built, Node.js will get confused and won't be able to build the main program properly. This is what causes the ERR_NOT_BUILDING_SNAPSHOT error.

Real-world example:

You're developing a Node.js application that uses a library that requires a snapshot (a special file that makes the application load faster). If you try to use the library before the snapshot is built, you'll get the ERR_NOT_BUILDING_SNAPSHOT error.

To fix this, you need to make sure that the snapshot is built before you use the library. You can do this by running the following command:

node --v8-options="snapshot_blob=my-snapshot.cc" your-script.js

This will build the snapshot and then run your script.

`ERR_NOT_IN_SINGLE_EXECUTABLE_APPLICATION`

This error occurs when you try to perform an operation that is only supported in a single-executable application, such as packaging your application into a single executable file.

Example

The following code will throw the ERR_NOT_IN_SINGLE_EXECUTABLE_APPLICATION error:

const { app } = require("electron");

app.pack(); // Throws an error

Solution

To fix this error, you need to create a single-executable application. You can do this by using the electron-packager tool.

Real-World Applications

Single-executable applications are useful for distributing your application to users who do not have Node.js installed. They are also useful for creating applications that can be installed on multiple platforms.

Simplified Explanation of ERR_NOT_SUPPORTED_IN_SNAPSHOT

Imagine you have a photo album of your favorite pictures. If you were to make a copy of the album (a "snapshot"), you wouldn't be able to add or remove any photos because the snapshot is just a frozen version of the original.

Similarly, when you create a "snapshot" of a running system, the snapshot is a frozen version of the state of the system at that moment. This means that certain operations that can be done on the running system, such as creating new files or modifying existing files, are not supported in the snapshot.

Potential Applications in Real World

Backing up data: Snapshots can be used to create backups of important data, ensuring that you have a copy even if the original is lost or corrupted.

Creating a development environment: Snapshots can be used to create isolated development environments for different projects. This ensures that changes made in one project don't affect other projects.

Rolling back changes: If a change to the system doesn't work as expected, a snapshot can be used to roll back the changes and restore the system to its previous state.

ERR_NO_CRYPTO

Explanation:

When you use Node.js to develop applications that involve encrypting or decrypting data, you need to make sure that Node.js was built with the OpenSSL library, which provides the necessary cryptographic functions.

If you try to use crypto features in Node.js without OpenSSL, you'll get this error message: ERR_NO_CRYPTO.

Simplified Explanation:

Imagine you have a secret box that you want to lock and unlock. You need a special key to do that. In Node.js, that key is the OpenSSL library. If you try to lock or unlock the box without the key (OpenSSL), you won't be able to.

Code Example:

// This code will throw ERR_NO_CRYPTO because Node.js isn't built with OpenSSL.
const crypto = require("crypto"); // Imports the Node.js crypto module
const encryptedData = crypto.encrypt("aes-256-cbc", "my secret key");

Real-World Applications:

Data Encryption:

Securely storing passwords and sensitive information in databases.
Encrypting communication channels to protect data from eavesdropping.

Data Integrity:

Verifying the authenticity of data by generating and checking digital signatures.
Detecting tampering with data by using hash functions.

Authentication:

Creating and verifying digital certificates to establish secure connections.
Generating and verifying digital signatures to authenticate users and documents.

Simplified Explanation of ERR_NO_ICU

When you try to use certain features in Node.js that require a library called ICU, you might get an ERR_NO_ICU error. ICU is like a special toolbox that Node.js uses to do things like sort text in different languages or format numbers. But if Node.js wasn't built with this toolbox, it can't use those features.

Real-World Example

Imagine you have a website that shows prices in different currencies. You want to use Node.js to sort the prices from lowest to highest, but Node.js doesn't have the ICU toolbox. You'll get an ERR_NO_ICU error because Node.js can't sort the prices without it.

Potential Applications

ICU is used in many real-world applications, such as:

Translating text into different languages
Formatting numbers and dates in different countries
Sorting text in a specific language

Code Implementation

Here's an example that shows how to handle the ERR_NO_ICU error:

try {
  // Code that uses ICU features
} catch (err) {
  if (err.code === 'ERR_NO_ICU') {
    // Handle the error by providing a fallback or showing a message to the user
  }
}

In this example, we try to use ICU features in the try block. If an error occurs, we check if it's an ERR_NO_ICU error. If it is, we can take appropriate actions, like providing a different way to do the task or informing the user that the feature is not supported.

ERR_NON_CONTEXT_AWARE_DISABLED

Simplified Explanation:

Imagine you have a special box that can only do certain things. You try to put something else into the box, but it doesn't work because the box only allows certain things. This is what happens when you try to use a special type of code called "non-context-aware native addon" in a part of your program where it's not allowed.

Technical Details:

Native addons: Pieces of code written in languages like C or C++ that can be used with JavaScript.
Context-aware native addons: Addons that can understand the specific part of your program where they're being used.
Non-context-aware native addons: Addons that don't know where they're being used in your program.

Real-World Example:

Think of a website that has a special section for secure payments. You want to use a code to handle the payments. The website only allows code that knows it's being used in the secure payment section. If you try to use code that doesn't know its location, the website won't allow it because it could be used to access sensitive data outside the payment section.

Potential Applications:

Security: Preventing unauthorized access to sensitive parts of your program.
Isolation: Ensuring that different parts of your program don't interfere with each other.

Example Code:

// This code will throw an ERR_NON_CONTEXT_AWARE_DISABLED error
const addon = require("non-context-aware-addon");

// This code will work because the addon is context-aware
const contextAwareAddon = require("context-aware-addon");

Simplified Explanation of ERR_OUT_OF_RANGE:

Imagine you have a box that can hold 10 toys. You try to put 12 toys into the box, but the box is too small. The box will not let you put in more toys than it can hold.

In the same way, ERR_OUT_OF_RANGE means that you are trying to do something that cannot be done because it is outside the allowed range.

Example:

const boxCapacity = 10;
const toys = 12;

if (toys > boxCapacity) {
  throw new Error("ERR_OUT_OF_RANGE: The box cannot hold more than 10 toys.");
}

In this example, if you try to put more than 10 toys in the box, you will get an ERR_OUT_OF_RANGE error.

Real-World Applications:

Validating user input (e.g., ensuring that a number is within a certain range)
Enforcing limits on resources (e.g., preventing users from creating too many files)
Detecting errors in numerical calculations

ERR_PACKAGE_IMPORT_NOT_DEFINED

Meaning:

You're trying to import a module from another package, but the other package doesn't have a record of that import in its package.json file.

Example:

// package.json
{
  "imports": {
    "#example-module": "./example-module.js"
  }
}

// my-file.js
import { something } from "#example-module"; // This will work as expected.

// another-file.js
import { something } from "#another-module"; // This will throw ERR_PACKAGE_IMPORT_NOT_DEFINED.

Simplified Explanation:

Imagine you have two Lego sets. One set is called "Example Module" and the other is called "Main Module." You want to use a piece from the "Example Module" set in the "Main Module" set.

In order for you to do this, you need to tell the "Main Module" set that it can use pieces from the "Example Module" set. You do this by putting the name of the "Example Module" set and the path to its pieces in the "Main Module" set's instruction booklet.

If you don't put the name and path of the "Example Module" set in the "Main Module" set's instruction booklet, then you won't be able to use pieces from the "Example Module" set in the "Main Module" set.

Potential Applications:

Importing reusable components from one package into another.
Creating modular applications where different components are packaged separately.
Sharing code between different teams and projects.

`ERR_PACKAGE_PATH_NOT_EXPORTED` Error

Simplified Explanation:

Imagine a store where you can buy different items, like toys, clothes, and books. Each item has its own section in the store.

Now, let's say the store has a rule that only certain sections are open to the public. So, if you try to go into a closed section, the store manager will stop you and say, "Sorry, you can't go in there."

The same thing happens when you try to import a module from a package in Node.js. Each package has its own set of files, like functions and scripts. Some files are meant to be used inside the package, while others are meant to be used by other programs.

If you try to import a file that is not meant to be used outside the package, you will get the ERR_PACKAGE_PATH_NOT_EXPORTED error. It's like trying to go into a closed section of the store.

Code Example:

// package.json
{
  "exports": {
    ".": "./index.js"
  }
}

// my-module/index.js
export const foo = 'bar';

// another-module.js
import { foo } from 'my-module/internal-file.js'; // Will throw ERR_PACKAGE_PATH_NOT_EXPORTED

In this example, the "exports" field in package.json only exports the index.js file. This means that other modules cannot import files directly from the my-module package.

Applications in the Real World:

This error can help you ensure that your packages are structured properly and that only the intended modules are available for import.

Error: Invalid Option Value

When you're using a function called parseArgs to understand command-line options, it can get picky about what kind of values you give it.

Imagine you have an option called name that you want to be a string, like "Bob." But by mistake, you give it a number, like 1234. The parseArgs function will get confused and throw this error. It's like saying, "Hey, I asked for a name, not a number!"

Or, if you have an option called enabled that you want to be a boolean, like true or false, but you give it a string, like "yes," the parseArgs function will say, "Uh-oh, I need a true or false here, not a string."

Code Snippets:

// Expecting a string
const args = parseArgs({ name: "Bob" });

// Will throw: ERR_PARSE_ARGS_INVALID_OPTION_VALUE
const args = parseArgs({ name: 1234 });

// Expecting a boolean
const args = parseArgs({ enabled: true });

// Will throw: ERR_PARSE_ARGS_INVALID_OPTION_VALUE
const args = parseArgs({ enabled: "yes" });

Real-World Applications:

Command-line utilities: To make sure that options are of the correct type.
Configuration files: To validate that settings are in the proper format.

1. ERR_PARSE_ARGS_UNEXPECTED_POSITIONAL

Thrown when you use the util.parseArgs() function to parse command line arguments and you provide a positional argument, but you have set the allowPositionals flag to false.
In simple terms, you're trying to pass an argument in a way that the function doesn't allow.

2. ERR_PARSE_ARGS_UNKNOWN_OPTION

Thrown when you use util.parseArgs() to parse command line arguments and you provide an option that is not recognized by the function.
Imagine you're trying to use a switch in your code and you specify a case for an option that doesn't exist in the switch statement.

Real-world examples:

ERR_PARSE_ARGS_UNEXPECTED_POSITIONAL:

Say you have a program that expects only options and you run it like this:

node my_program --flag1=abc positional-argument

If you set allowPositionals to false, the program will throw the ERR_PARSE_ARGS_UNEXPECTED_POSITIONAL error because it doesn't expect any positional arguments.

ERR_PARSE_ARGS_UNKNOWN_OPTION:

Let's say you have a program that has an option --flag1, and you try to run it like this:

node my_program --unknown-option

The program will throw the ERR_PARSE_ARGS_UNKNOWN_OPTION error because it doesn't recognize the --unknown-option option.

Potential applications:

Command line argument parsing: Validating user input to ensure they provide valid options and arguments.
Configuration parsing: Verifying that configuration files have the expected options and values.
Data validation: Checking that data conforms to a specific structure or format.

Error: ERR_PARSE_ARGS_UNKNOWN_OPTION

Simplified Explanation:

Imagine you're playing a game and you need to type in a secret code to open a door. But you don't know the code, so you type in something random. The door won't open and you get a message saying "Unknown Option."

This is like what happens in Node.js when you use util.parseArgs() to try to parse command-line arguments. If you have the strict option set to true (which means "be super strict"), it will only allow you to use arguments that you have already defined. If you try to use an argument that isn't defined, you'll get this error.

Code Snippet:

const { parseArgs } = require("util");

const options = {
  // Define the allowed arguments here
};

const args = ["--unknown-option"];

try {
  const parsedArgs = parseArgs(args, options, { strict: true });
  // Do something with the parsed arguments
} catch (err) {
  // Handle the error, which will be `ERR_PARSE_ARGS_UNKNOWN_OPTION`
}

Real-World Application:

This error is helpful in command-line applications where you want to ensure that users only use valid arguments. For example, if you have a command that takes a file path as an argument, you can use this error to prevent users from entering invalid file paths.

Simplified Explanation of `ERR_PERFORMANCE_INVALID_TIMESTAMP`

Imagine your computer is like a big playground, and there are many kids playing different games. These games can take different amounts of time to complete.

To keep track of how long each game takes, the playground has a special timekeeper named "Performance". Performance keeps a list of when each game starts and ends.

But sometimes, a kid might accidentally tell Performance the wrong time for when their game started or ended. This can mess up all the other kids' times because Performance uses those timestamps to calculate how long each game took.

When this happens, Performance throws an error called ERR_PERFORMANCE_INVALID_TIMESTAMP. This error tells the kid that they gave Performance the wrong time and that they need to fix it.

Real-World Example

Here is a simplified code example that shows how ERR_PERFORMANCE_INVALID_TIMESTAMP can occur:

// Create a performance mark with an invalid timestamp
performance.mark("start", -10000);

// Attempt to create a performance measure using the invalid mark
performance.measure("my-measure", "start");

In this example, we create a performance mark with an invalid timestamp of -10000. When we then try to create a performance measure using that mark, we get the ERR_PERFORMANCE_INVALID_TIMESTAMP error.

Potential Applications

Performance marks and measures are useful for measuring the performance of code in a web application. They can be used to identify bottlenecks and optimize the application for better performance.

Here is an example of how performance marks and measures can be used in a real-world application:

A web developer wants to measure the time it takes for a web page to load. They can use performance marks to mark the start and end of the page load process. They can then use performance measures to calculate the total time it took for the page to load.

This information can help the developer identify any bottlenecks in the page load process and make improvements to speed up the page.

Simplified Content:

When you're trying to measure how fast your code is running, you might encounter this error if you give the function that measures the performance invalid options.

Explanation:

Imagine you're using a stopwatch to measure how long it takes you to do a task. If you accidentally set the stopwatch to count up instead of down, it will give you the wrong result. This error is like that - the options you provided for measuring the performance of your code were incorrect, so the result will be wrong.

Code Example:

// Incorrect options
const incorrectOptions = {
  type: "incorrect_type", // Type should be 'function' or 'callback'
  timeout: 0, // Timeout should be greater than 0
};

// Correct options
const correctOptions = {
  type: "function", // Type is 'function'
  timeout: 1000, // Timeout is 1000 milliseconds (1 second)
};

// Measure performance with incorrect options
const performanceMeasure = require("util").performanceMeasure;
try {
  performanceMeasure(incorrectOptions, (err, data) => {
    if (err) {
      console.error(err);
    }
  });
} catch (err) {
  console.error(err);
}

// Measure performance with correct options
try {
  performanceMeasure(correctOptions, (err, data) => {
    if (err) {
      console.error(err);
    }
  });
} catch (err) {
  console.error(err);
}

Real-World Applications:

Performance Optimization: Finding bottlenecks in your code and fixing them to make your application run faster.
Code Profiling: Analyzing how different parts of your code perform to identify inefficiencies and optimize performance.
Benchmarking: Comparing the performance of different code implementations or versions of your application to identify the best one.

`ERR_PROTO_ACCESS`

Simplified Explanation

Imagine objects as houses. Every house has a blueprint, called a prototype. The prototype tells the house what it should look like and what it can do.

Before, you could directly change the blueprint of a house by using __proto__. But now, that's like breaking into a house and changing the blueprint while everyone's sleeping. It's not allowed!

Instead, there are new ways to get and change the blueprint:

Object.getPrototypeOf: This lets you see the blueprint without changing it.
Object.setPrototypeOf: This lets you change the blueprint, but only if you have the right permission.

Code Example

// Get the blueprint of an object
const blueprint = Object.getPrototypeOf(myObject);

// Change the blueprint of an object (if allowed)
Object.setPrototypeOf(myObject, newBlueprint);

Applications in the Real World

Customizing Objects: You can create custom blueprints to add new features to existing objects.
Extending Functionality: You can create new objects based on existing ones, inheriting their properties and methods.
Security: Preventing unauthorized changes to blueprints ensures the integrity of objects and their data.

What is ERR_REQUIRE_ESM?

Imagine you have a house with two rooms: the living room and the kitchen. The living room is where you relax and the kitchen is where you cook.

In JavaScript, there are two types of rooms for code: CommonJS and ES Modules. CommonJS is like the living room, where you can bring in any furniture you want. ES Modules are like the kitchen, where everything is already set up and you can't add your own stuff.

When you try to bring kitchen furniture into the living room, you get an error. That error is called ERR_REQUIRE_ESM.

Example:

// This code will throw an error because you're trying to use an ES Module in a CommonJS environment.
require("./my-module.js");

How to fix it:

You can fix the error by converting your ES Module to a CommonJS module.

// Convert my-module.js to a CommonJS module
module.exports = {
  // Your code here
};

// Now you can require the module without getting an error
require("./my-module.js");

Real-world applications:

ES Modules are great for organizing code in large projects. They also make it easier to share code between different projects.

Potential applications:

Building reusable libraries
Creating modular applications
Sharing code between microservices

ERROR OCCURED

`ERR_SCRIPT_EXECUTION_INTERRUPTED`

Script execution was interrupted by SIGINT (For example, Ctrl+C was pressed.)

Can you please simplify and explain the given content from nodejs's errors module?

explain each topic in detail and simplified manner (simplify in very plain english like explaining to a 5 year old child).
retain code snippets or provide if you have better and improved versions or examples.
give real world complete code implementations and examples for each.
provide potential applications in real world for each.
ignore version changes, changelogs, contributions, extra unnecessary content.
```
  The response was blocked.
```

ERR_SCRIPT_EXECUTION_TIMEOUT

When a script takes too long to run, Node.js will kill it and throw this error. This can happen for a few reasons:

The script has an infinite loop or other bug that causes it to never finish.
The script is doing a lot of heavy computation, like processing a large dataset.
The computer running Node.js is slow or under a lot of load.

Here's an example of a script that will cause this error:

while (true) {
  console.log("This script will never end!");
}

To fix this error, you need to find and fix the bug in your script. If you're not sure what the bug is, you can try logging the values of variables at different points in the script to see what's going wrong.

Here's an improved version of the example above:

let i = 0;
while (i < 10) {
  console.log("This script will end after 10 iterations.");
  i++;
}

This script will not cause the ERR_SCRIPT_EXECUTION_TIMEOUT error because it has a finite loop that will end after 10 iterations.

This error is often encountered when developing Node.js applications. It can be frustrating, but it can also be a helpful way to find and fix bugs in your code.

`ERR_SERVER_ALREADY_LISTEN`

This error occurs when you try to start a server that is already running.

Imagine you have a toy car that you can control with a remote control. If you try to turn on the car while it is already on, nothing will happen. That's because the car is already running.

The same thing happens with servers. If you try to start a server that is already running, the server will not start. Instead, you will get the ERR_SERVER_ALREADY_LISTEN error.

Here is an example of code that can cause this error:

const net = require("net");

const server = net.createServer();

// Start the server
server.listen(3000);

// Try to start the server again
server.listen(3000);

When you run this code, you will get the following error:

Error: listen EADDRINUSE: address already in use :::3000

This error means that the server is already running on port 3000.

To fix this error, you can stop the server before starting it again. You can do this by calling the server.close() method.

Here is an example of code that will fix the error:

const net = require("net");

const server = net.createServer();

// Start the server
server.listen(3000);

// Stop the server
server.close();

// Start the server again
server.listen(3000);

Now, when you run this code, the server will start successfully.

Applications in the real world

Servers are used in many different applications in the real world. Some examples include:

Web servers: These servers host websites and deliver them to users' browsers.
Email servers: These servers send and receive email messages.
Database servers: These servers store and manage data.
File servers: These servers store and share files.
Game servers: These servers host online games.

Simplified Explanation:

Imagine you have a water faucet that you can turn on and off. When you turn it on, water flows out. When you turn it off, the water stops flowing.

Now, imagine that you tried to turn off the faucet when it was already off. What would happen? Nothing would happen because the faucet was already off.

The same thing happens with a net.Server in Node.js. A net.Server is like a water faucet that listens for incoming network connections. You can start the server with the .listen() method, which is like turning on the faucet. When you start the server, it starts listening for connections.

You can stop the server with the .close() method, which is like turning off the faucet. When you stop the server, it stops listening for connections.

If you try to stop the server with the .close() method when it is already stopped, it will throw the ERR_SERVER_NOT_RUNNING error. This is because there is no point in trying to stop a server that is already stopped.

Real-World Example:

Here is an example of how you might use a net.Server in a real-world application:

const net = require("net");

const server = net.createServer((socket) => {
  // Do something with the socket
});

server.listen(3000);

In this example, we create a net.Server and listen for incoming connections on port 3000. When a connection is established, the createServer() callback is called with a socket object that represents the connection.

We could then use the socket object to send and receive data over the network.

Potential Applications:

net.Server instances can be used in a variety of real-world applications, including:

Web servers
Chat servers
Game servers
File sharing applications

Code Snippets:

Here is a complete code example that demonstrates how to use a net.Server to create a simple web server:

const net = require("net");
const http = require("http");

const server = net.createServer((socket) => {
  const request = http.request(socket);
  const response = http.response(socket);

  request.on("data", (data) => {
    // Do something with the request data
  });

  request.on("end", () => {
    // Do something when the request is finished
  });

  response.writeHead(200, { "Content-Type": "text/plain" });
  response.write("Hello, world!");
  response.end();
});

server.listen(3000);

We then use the socket object to create an HTTP request and response object. We can then use these objects to send and receive HTTP data over the network.

In this example, we simply send a "Hello, world!" message back to the client.

`ERR_SINGLE_EXECUTABLE_APPLICATION_ASSET_NOT_FOUND`

Simplified Explanation

You tried to use a key to access an asset (like an image or sound file) in your single executable application, but the key didn't match any assets in the application. It's like looking for a toy in a box, but the toy you want isn't there.

Detailed Explanation

A single executable application (or SEA) is a type of application that packages all its assets (like images, sounds, and code) into a single executable file. To access these assets, you use keys that identify the asset you want.

The ERR_SINGLE_EXECUTABLE_APPLICATION_ASSET_NOT_FOUND error occurs when you use a key that doesn't match any asset in the SEA. This could happen if you mistyped the key, or if the asset was removed from the SEA.

Code Example

const { readFileSync } = require("fs");
const { execFile } = require("child_process");

const seaPath = "./my-sea-app";
const assetKey = "my-asset";

try {
  const assetData = readFileSync(seaPath, assetKey);
  console.log(`Asset data: ${assetData}`);
} catch (err) {
  if (err.code === "ERR_SINGLE_EXECUTABLE_APPLICATION_ASSET_NOT_FOUND") {
    console.error(`Asset with key '${assetKey}' not found in SEA`);
  } else {
    throw err;
  }
}

Real-World Applications

SEAs are often used to distribute games and other applications that need to access a lot of assets. By packaging all the assets into a single file, the application can be easily deployed and updated.

Potential Applications

Distributing video games
Deploying web applications
Packaging mobile applications

`ERR_SOCKET_ALREADY_BOUND`

Simplified Explanation:

When you want to use a socket, you need to set it up first by "binding" it to a specific address and port. It's like giving your socket a home and a way to receive messages.

If you try to bind a socket that already has a home, you'll get this error. It's like trying to move your house into a house that's already occupied.

Code Snippet:

const net = require("net");

const server = net.createServer();

// Bind the server to port 3000
server.listen(3000);

// Try to bind the server again (this will fail with ERR_SOCKET_ALREADY_BOUND)
server.listen(8080);

Improved Code Snippet:

To avoid this error, first check if the socket is already bound before trying to bind it again:

const net = require("net");

const server = net.createServer();

// Check if the server is already bound
if (server.listening) {
  console.log("Server is already bound");
} else {
  // Bind the server to port 3000
  server.listen(3000);
}

Real-World Applications:

This error is common when you have multiple servers running on the same computer and they try to bind to the same port. It's essential to ensure that each server has a unique port.

`ERR_SOCKET_BAD_BUFFER_SIZE`

Simplified Explanation:

You told the computer to use a negative number as the "buffer size" for receiving or sending data over the network. The computer doesn't like this because it's like asking it to store things in a "box" with a negative size, which doesn't make sense.

Detailed Explanation:

Buffer size: When your computer sends or receives data over the network, it stores it in a temporary space called a "buffer" before processing it.
Negative size: A negative number is not allowed for the buffer size because it would mean the computer is told to reserve a "box" of a negative size. This doesn't make sense because you can't have a "box" with a negative size.
Error message: The error message ERR_SOCKET_BAD_BUFFER_SIZE is displayed when you try to create a network socket using the dgram.createSocket() function and provide a negative value for the recvBufferSize or sendBufferSize options.

Real-World Example:

Imagine you're building a software that sends messages over the internet. You need to create a network socket to send these messages. If you accidentally provide a negative number as the buffer size, the software will fail with the ERR_SOCKET_BAD_BUFFER_SIZE error. This means you need to fix your code before you can send messages successfully.

Potential Applications:

Networking software: Used to create network sockets for sending and receiving data over the internet.
Messaging applications: Used to send and receive messages between devices.
Online gaming: Used to create network connections for multiplayer games.

Simplified Explanation of ERR_SOCKET_BAD_PORT:

When you're using a computer to connect to a remote server or device, you specify a port number. This is like a special address that tells the computer where to find the server you want to connect to.

Just like a street address has a number (like 123 Main Street), a port number is a number (like 80 or 443) that identifies a specific place on the server or device you're trying to connect to.

The error ERR_SOCKET_BAD_PORT means that the port number you gave to the computer is not valid. It could be less than 0, greater than 65535, or it could be a number that is not assigned to any server or device.

Real-World Example:

Imagine you're trying to connect to a website. The website's address is like the street address (e.g., www.example.com), and the port number is like the house number. If you enter the wrong house number, you won't be able to find the website.

Potential Applications in Real World:

Networking: Ensuring that devices can connect to each other using the correct port numbers.
Web development: Verifying that web servers are running on the expected port numbers.
Troubleshooting: Identifying errors related to invalid port numbers.

Simplified Explanation:

ERR_SOCKET_BAD_TYPE Error:

Imagine you have a special box called a "socket" that you can use to send messages over the internet.
This socket can be either a "udp4" or "udp6" type.
But if you try to use the socket in a way that's not allowed for its type (like trying to send a message using a "udp4" socket instead of a "udp6" socket), you'll get this error.

ERR_SOCKET_BUFFER_SIZE Error:

When you send messages over the internet, they get stored in a special place called a "buffer" before they're sent out.
If the buffer gets too full and you try to send a new message, you'll get this error.

Real-World Code Implementations:

ERR_SOCKET_BAD_TYPE Error:

const socket = new dgram.Socket("udp6"); // Create a "udp6" socket
socket.send("Hello!", "127.0.0.1", 3000); // Error: ERR_SOCKET_BAD_TYPE

ERR_SOCKET_BUFFER_SIZE Error:

const socket = new dgram.Socket("udp4");
for (let i = 0; i < 100000; i++) {
  // Send a lot of messages
  socket.send("Hello!", "127.0.0.1", 3000);
}
// Error: ERR_SOCKET_BUFFER_SIZE

Potential Applications:

ERR_SOCKET_BAD_TYPE Error:

Detecting and handling incorrect socket usage in network applications.

ERR_SOCKET_BUFFER_SIZE Error:

Limiting the amount of data sent over a network to prevent performance issues.

`ERR_SOCKET_BUFFER_SIZE`

This error occurs when the size of the receive or send Buffer could not be determined while using dgram.createSocket().

Explanation

When using dgram.createSocket(), you need to specify the size of the receive or send buffer. This is the maximum amount of data that can be received or sent at a time. If you don't specify a size, the default size will be used.

However, if the size of the receive or send buffer cannot be determined, the ERR_SOCKET_BUFFER_SIZE error will be thrown. This can happen if you are using a custom socket implementation or if there is a problem with the underlying operating system.

Real-World Example

The following code will throw the ERR_SOCKET_BUFFER_SIZE error:

const dgram = require("dgram");

const socket = dgram.createSocket();

socket.on("error", (err) => {
  if (err.code === "ERR_SOCKET_BUFFER_SIZE") {
    // Handle the error
  }
});

Potential Applications

The ERR_SOCKET_BUFFER_SIZE error can be used to handle errors that occur when the size of the receive or send buffer cannot be determined. This can be useful for debugging purposes or for creating custom socket implementations.

ERR_SOCKET_CLOSED

Plain English Explanation:

Imagine you have a water faucet and you turn it on to fill a cup. But before the cup is full, you accidentally turn off the faucet. Now, if you try to continue filling the cup, the water won't come out because the faucet is closed.

In the same way, in Node.js, a socket is like a water faucet. It allows you to send and receive data over a network. When you close the socket, it's like turning off the faucet. After that, you can't send or receive data through that socket anymore.

Code Snippet:

const net = require("net");

const server = net.createServer();

server.on("connection", (socket) => {
  // Socket is open and ready for communication.

  // ...

  // Close the socket.
  socket.end();
});

// Now, if you try to use the socket, you'll get the ERR_SOCKET_CLOSED error.
// for example:
try {
  socket.write("Hello world!");
} catch (err) {
  // Error: ERR_SOCKET_CLOSED
}

Real-World Applications:

Web servers: Web servers use sockets to communicate with clients (web browsers). When a client connects to a web server, a socket is created. The socket is used to send and receive data, such as the HTML code for the website. When the client disconnects, the socket is closed to save resources.
Databases: Databases use sockets to communicate with clients (applications). When a client connects to a database, a socket is created. The socket is used to send and receive data, such as SQL queries and the results of those queries. When the client disconnects, the socket is closed to prevent data leakage and unauthorized access.
Online games: Online games use sockets to communicate between players. When a player joins the game, a socket is created. The socket is used to send and receive data, such as the player's movements, actions, and chat messages. When the player leaves the game, the socket is closed to prevent cheating and ensure the integrity of the game.

Simplified Explanation for `ERR_SOCKET_CLOSED_BEFORE_CONNECTION` Error

What is ERR_SOCKET_CLOSED_BEFORE_CONNECTION?

Imagine you have a water pipe, and you turn on the water tap. But before the water can come out, someone disconnects the pipe. That's like what happens with ERR_SOCKET_CLOSED_BEFORE_CONNECTION.

What causes it?

This error happens when you try to send data to a network connection, but the connection hasn't been fully established yet. It's like trying to send a letter to a friend's house, but the mailbox is still being built.

How to fix it

To fix this error, you need to make sure the connection is properly established before sending data. You can use the [net.Socket.connect()][] method to connect the socket before writing to it.

Real-World Example

Here's a simplified example of how this error might happen:

const net = require("net");

// Create a new socket
const socket = new net.Socket();

// Try to send data without connecting
socket.write("Hello world");

// This will trigger the `ERR_SOCKET_CLOSED_BEFORE_CONNECTION` error

To fix this error, you can connect the socket before writing:

const net = require("net");

// Create a new socket
const socket = new net.Socket();

// Connect the socket
socket.connect();

// Now you can send data
socket.write("Hello world");

Potential Applications

This error can be useful in situations where you need to ensure that data is only sent once a connection is established. For example, in secure communication protocols, data is often encrypted before being sent over the network. In these cases, it's important to make sure that the connection is established before sending the encrypted data, to prevent eavesdropping.

Error: ERR_SOCKET_CONNECTION_TIMEOUT

Simplified Explanation:

Imagine you're trying to call a friend on the phone. You dial their number and wait, but no one answers. After a certain amount of time (the "timeout"), you give up and hang up.

In the same way, when a computer tries to connect to a server on the internet, it waits for a certain amount of time. If the server doesn't respond within that time, the computer gives up and reports the error "ERR_SOCKET_CONNECTION_TIMEOUT".

Detailed Explanation:

When a computer connects to a server on the internet, it uses a "socket" to establish the connection. The socket is like a pipe that allows data to flow between the computer and the server.

To create a socket, the computer needs to know the IP address of the server. It gets this address by querying a DNS (Domain Name System) server, which translates domain names (like "www.example.com") into IP addresses.

Once the computer has the IP address, it sends a request to the server to create a connection. If the server doesn't respond within a certain amount of time (usually a few seconds), the computer gives up and reports the "ERR_SOCKET_CONNECTION_TIMEOUT" error.

Code Snippet:

try {
  const socket = new Socket();
  socket.connect(80, "www.example.com", () => {
    // Connection successful
  });
} catch (err) {
  if (err.code === "ERR_SOCKET_CONNECTION_TIMEOUT") {
    // Handle timeout error
  }
}

Real-World Applications:

Web browsing: When you type a website address into your browser, the browser sends a request to the website's server. If the server doesn't respond within a certain amount of time, you'll see a "Connection timeout" error message.
Email: When you send an email, the email client connects to the email server to send the message. If the server doesn't respond within a certain amount of time, you'll get an error message.
Online gaming: When you play an online game, your computer connects to the game server. If the server doesn't respond within a certain amount of time, you'll get disconnected from the game.

ERR_SOCKET_DGRAM_IS_CONNECTED

This error occurs when you try to connect a UDP socket that is already connected. UDP is a "connectionless" protocol, which means that it doesn't establish a permanent connection between two computers. Instead, each message is sent independently.

Real World Example

Imagine you have two friends, Alice and Bob. You want to send a message to Bob, so you take a piece of paper and write the message on it. Then, you throw the paper at Bob's house. This is like sending a UDP message.

Now, imagine that you already threw a paper at Bob's house and he caught it. If you try to throw another paper at his house, he will not catch it because he is already holding the first paper. This is like trying to connect a UDP socket that is already connected.

Potential Applications

UDP is used in many real-world applications, such as:

Online gaming
Voice over IP (VoIP)
Video streaming
Distributed systems

Improved Code Sample

const dgram = require("dgram");

const socket = dgram.createSocket("udp4");

socket.connect(3000, "localhost", (err) => {
  if (err) {
    if (err.code === "ERR_SOCKET_DGRAM_IS_CONNECTED") {
      console.log("The socket is already connected.");
    } else {
      console.log("An unknown error occurred:", err);
    }
  } else {
    console.log("The socket has been connected.");
  }
});

ERR_SOCKET_DGRAM_NOT_CONNECTED

Simplified Explanation:

Your program tried to send or receive data on a "disconnected" socket. Imagine a socket as a pipe that connects two programs. If the pipe is disconnected, you can't send or receive anything through it.

In-depth Explanation:

Sockets are used for communication between two programs over a network. In Node.js, the dgram module provides support for Datagram sockets, which allow you to send and receive data in small chunks.

When you use dgram, you first create a socket using dgram.createSocket(). This creates a "disconnected" socket. You then need to connect the socket to a remote address (IP address and port) using dgram.connect(). This establishes the connection between the two programs.

Once the socket is connected, you can send data using dgram.send() and receive data using dgram.recv(). If you try to send or receive data on a disconnected socket, Node.js will throw an ERR_SOCKET_DGRAM_NOT_CONNECTED error.

Code Example:

Here's a simple example of how this error can occur:

const dgram = require("dgram");

// Create a disconnected socket
const socket = dgram.createSocket("udp4");

// Trying to send data on a disconnected socket will throw an error
socket.send("Hello World", 3000, "localhost");
// 'localhost' is the default value.

Potential Applications:

Datagrams are often used in real-time applications, such as online games and video conferencing, where small amounts of data need to be sent and received frequently.

ERR_SOCKET_DGRAM_NOT_RUNNING

Simplified Explanation:

Your program tried to do something with a socket that has been closed. Imagine a socket as a water tap. If you close the tap, you can't turn it back on.

In-depth Explanation:

When you're done using a socket, you should call the socket.close() method to release its resources and close the connection. If you try to do anything with a closed socket, Node.js will throw an ERR_SOCKET_DGRAM_NOT_RUNNING error.

Code Example:

Here's a simple example of how this error can occur:

const dgram = require("dgram");

// Create a socket
const socket = dgram.createSocket("udp4");

// Close the socket
socket.close();

// Trying to send data on a closed socket will throw an error
socket.send("Hello World", 3000, "localhost");

Potential Applications:

Sockets are often used in long-running applications, such as servers and chat clients, where they need to be kept open for an extended period.

Simplified Explanation:

Imagine you're trying to send a message to your friend using walkie-talkies. If the walkie-talkies aren't turned on, you won't be able to send the message.

Similarly, in Node.js, if you try to send a message using the UDP protocol (which uses walkie-talkies-like technology), but the UDP subsystem is not running, you will get this error.

Potential Applications:

UDP is often used in real-world applications for things like:

Online games (for sending player movements and updates quickly)
Video conferencing (for transmitting audio and video data in real-time)
Broadcasting live events (for streaming video and audio)

Complete Code Implementation:

try {
  // Send a UDP message
  dgram.createSocket("udp4").send("Hello, world!", PORT);
} catch (err) {
  if (err.code === "ERR_SOCKET_DGRAM_NOT_RUNNING") {
    // Handle the error: UDP subsystem is not running
  }
}

`ERR_SRI_PARSE`

Simplified Explanation:

When you're checking the security of a webpage, you can use a "Subresource Integrity" (SRI) check to make sure that only content from trusted sources is loaded. Imagine you're a parent checking what websites your child can visit. You give them a list of websites that are okay to go to, like "example.com" and "fun-games.net." If they try to go to a website that's not on the list, like "bad-guys.net," you can stop them from going there. That's what an SRI check does for websites.

But sometimes, the list of trusted websites (called an "integrity attribute") is written in a way that the computer can't understand. It's like if you wrote your child's website list in a secret code that they couldn't read. This error means that the computer couldn't understand the integrity attribute.

Code Snippet:

try {
  // Code that checks integrity attributes
} catch (err) {
  if (err.code === "ERR_SRI_PARSE") {
    // Handle the error
  }
}

Applications in Real World:

Website security
Protecting against malicious content
Ensuring that only trusted data is loaded onto a webpage

Simplified Explanation:

Imagine a stream as a pipe with water flowing through it. When you finish the stream, it's like turning off the tap. You can't turn the tap back on and expect water to flow again.

Code Implementation:

const fs = require("fs");

const stream = fs.createReadStream("file.txt");

// Read from the stream
stream.on("data", (data) => {
  // Do something with the data
});

// When the stream ends, close it
stream.on("end", () => {
  stream.close();
});

// Trying to read from a closed stream will throw an error
stream.on("data", (data) => {
  // Do something with the data
});
// Error: ERR_STREAM_ALREADY_FINISHED

Potential Applications:

Ensuring that streams are properly closed to avoid resource leaks.
Handling errors when trying to access data from a closed stream.
Preventing unintended data access from closed streams.

`ERR_STREAM_CANNOT_PIPE`

Explanation:

This error occurs when you try to connect two streams (a data source and a destination) using the stream.pipe() method, but the destination stream is not writable.

Simplified Explanation:

Imagine you have a stream of water flowing from a faucet. You can't connect a cup of water to the faucet because the cup is not something you can write data into. You need a bucket or something similar to hold the water.

Code Snippet:

const fs = require('fs');

const readableStream = fs.createReadStream('input.txt');
const writableStream = fs.createWriteStream('output.txt');

readableStream.pipe(writableStream); // This will work

const notWritableStream = fs.createReadStream('input2.txt');

readableStream.pipe(notWritableStream); // This will throw ERR_STREAM_CANNOT_PIPE

Potential Applications in Real World:

Connecting a data source to a logging system
Piping data from a file to a web server
Streaming video or audio from a server to a media player

`ERR_STREAM_DESTROYED`

Simplified Explanation:

Imagine you have a water pipe that's connected to your house. You turn on the tap to get some water, but suddenly the pipe bursts. If you try to turn the tap on again, it won't work because the pipe is already broken.

The same thing can happen with streams in Node.js. A stream is like a pipe that sends or receives data. If you call stream.destroy(), you're breaking the pipe. After that, if you try to use the stream again, you'll get the ERR_STREAM_DESTROYED error because the stream is no longer working.

Real-World Example:

Let's say you have a program that reads data from a file and writes it to a database. The file and database are connected to your program through streams.

const fs = require('fs');
const db = require('some-database');

const fileStream = fs.createReadStream('./data.txt');
const dbStream = db.createWriteStream('./data.db');

fileStream.pipe(dbStream);

Once you run this program, data from data.txt will be read and written to data.db. However, if you call dbStream.destroy() in the middle of the process, the database stream will be broken.

If you try to write more data to the database using dbStream, you'll get the ERR_STREAM_DESTROYED error:

dbStream.destroy();

fileStream.pipe(dbStream); // Error: ERR_STREAM_DESTROYED

Potential Applications:

The ERR_STREAM_DESTROYED error can be useful in scenarios where you want to handle errors and clean up resources properly. For example, if you're writing a web server and a client disconnects abruptly, you can use ERR_STREAM_DESTROYED to handle the error and close the connection gracefully.

Simplified Explanation:

ERR_STREAM_NULL_VALUES

When you're writing data to a stream, you're not allowed to send null values. Imagine a stream as a water pipe. You can only pour water through it, not empty air. null is like empty air in this case, and it's not allowed in the stream.

Real-World Example:

const fs = require("fs");

// Create a write stream to a file
const writeStream = fs.createWriteStream("myfile.txt");

// Try to write a null value to the stream
writeStream.write(null); // Throws ERR_STREAM_NULL_VALUES

// Instead, write a valid string value
writeStream.write("Hello world!");

Potential Applications:

Ensuring data integrity in streaming applications
Preventing data corruption in data pipelines
Validating data before writing to databases or other data stores

Simplified Explanation of ERR_STREAM_PREMATURE_CLOSE

Imagine you're playing with a water hose. When you turn it on, water flows out. But if you suddenly turn it off before all the water has come out, you might end up with some leftover water spilling out and making a mess.

The same thing can happen with data streams in Node.js. A stream is like a hose that carries data, and stream.finished() is like turning off the hose. If you turn off the hose before all the data has been received, you'll get an error called ERR_STREAM_PREMATURE_CLOSE.

Code Example

Here's a simple example of how this error can occur:

const fs = require("fs");

const readableStream = fs.createReadStream("my-file.txt");

readableStream.on("data", (chunk) => {
  // Do something with the data
});

// Close the stream before all the data has been read
readableStream.end();

readableStream.finished((err) => {
  if (err) {
    // Handle the `ERR_STREAM_PREMATURE_CLOSE` error
  }
});

In this example, we're reading a file using a readable stream. We close the stream before all the data has been read, which causes the ERR_STREAM_PREMATURE_CLOSE error.

Potential Applications in the Real World

Streams are used in a variety of applications, such as:

Reading and writing files
Sending and receiving data over the network
Processing large amounts of data in parallel

Understanding how to handle errors like ERR_STREAM_PREMATURE_CLOSE is essential for developing robust and reliable applications.

ERR_STREAM_PUSH_AFTER_EOF

This error is thrown when you try to push() data into a stream after it has already ended. This can happen if you forget to close the stream or if you try to push data into a closed stream.

The following code snippet demonstrates this error:

const { Writable } = require("stream");

const writable = new Writable();

writable.end();

writable.push("test"); // throws ERR_STREAM_PUSH_AFTER_EOF

How to fix it:

To fix this error, you should close the stream before trying to push more data into it. You can do this by calling the end() method on the stream.

const { Writable } = require("stream");

const writable = new Writable();

writable.write("test");

writable.end();

`ERR_STREAM_UNSHIFT_AFTER_END_EVENT`

Simplified Explanation:

Imagine your computer is a water pipe. You can send data (like water) through the pipe into a program. The 'end' event is like the faucet being turned off. After the faucet is turned off, you can't add more water to the pipe. The stream.unshift() function is like trying to add more water to the pipe after the faucet is off.

Real World Application:

This error can happen if you try to do too many things at once with your program. For example, if you're sending a lot of data to a program and it can't keep up, it might close the faucet before you're finished sending all the data.

Improved Code Snippet:

// Create a stream
const stream = require("stream");
const mystream = new stream.Writable();

// Listen for the 'end' event
mystream.on("end", () => {
  // The faucet is turned off.
  // Don't try to add more data now.
});

// Try to add more data after the 'end' event
mystream.end("Hello");
mystream.unshift("World"); // This will throw an error

// Instead, finish sending data before the 'end' event
mystream.write("Hello");
mystream.end("World"); // This will work

1. ERR_STREAM_WRAP

Simplified Explanation: When you try to use a stream (like a network socket) to read or write data, but you haven't set it up correctly, you might get this error.

Code Example:

const net = require("net");
const socket = new net.Socket();

// We forgot to set the encoding to 'utf8'
socket.write("Hello world"); // This will throw an `ERR_STREAM_WRAP` error

Real-World Application: When you're building a web server or a chat application, you need to set up streams to handle incoming and outgoing requests. If you don't set up the streams correctly, you might get this error and your application won't work as expected.

2. ERR_STREAM_WRITE_AFTER_END

Simplified Explanation: You tried to write data to a stream, but you had already called end() on that stream. This means that the stream is closed and can't accept any more data.

Code Example:

const fs = require("fs");
const file = fs.createWriteStream("myfile.txt");

file.end();
file.write("Hello world"); // This will throw an `ERR_STREAM_WRITE_AFTER_END` error

Real-World Application: When you're writing data to a file or a database, you need to be careful not to write any more data after you've closed the stream. This error can help you catch these mistakes and prevent data corruption.

ERR_STREAM_WRITE_AFTER_END

Simplified Explanation:

Imagine you have a water pipe that lets water out. If you turn off the pipe, you can't keep pouring water into it because it's already closed. The same thing happens with streams in Node.js.

Technical Explanation:

A stream is like a conveyor belt that allows data to flow in or out of a program. Node.js provides streams to handle different types of data, such as text, files, or network connections.

When you're done writing data to a stream, you call stream.end(). This tells the stream that there's no more data coming. After that, if you try to write more data to the stream using stream.write(), you'll get an ERR_STREAM_WRITE_AFTER_END error.

Real-World Example:

Let's say you're writing a program that generates a report and sends it to a file. You can use a stream to write the report line by line. When the report is complete, you call stream.end() to close the file.

After that, if you try to add more lines to the report, you'll get an ERR_STREAM_WRITE_AFTER_END error because the file is already closed.

Code Example:

const fs = require("fs");

const stream = fs.createWriteStream("report.txt");

// Write some lines to the report
stream.write("Line 1\n");
stream.write("Line 2\n");

// Close the report
stream.end();

// Trying to write more data after the stream is closed
stream.write("Line 3\n"); // Throws ERR_STREAM_WRITE_AFTER_END

Potential Applications:

Streams are used in a wide variety of applications, including:

Writing files
Reading files
Sending data over a network
Piping data between different programs

What is ERR_STRING_TOO_LONG?

It's an error that happens when you try to create a string (like a sentence or a word) that is too long. It's like trying to write a super long story on a tiny piece of paper.

Simplified Explanation:

Imagine you have a box that can hold 100 letters. If you try to put more than 100 letters in the box, it won't fit. In the same way, when you try to create a string that is longer than the maximum allowed length, you'll get the ERR_STRING_TOO_LONG error.

Code Example:

let myString =
  "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";

console.log(myString); // "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz"

In this example, the string myString has 52 characters, which is within the maximum allowed length.

let myString =
  "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz";

console.log(myString); // ERR_STRING_TOO_LONG

In this example, the string myString has 104 characters, which is longer than the maximum allowed length, so you'll get the ERR_STRING_TOO_LONG error.

Real-World Applications:

When you're writing code that takes input from users, you need to make sure that the input is a reasonable length.
When you're storing data in a database, you need to make sure that the data fits into the columns.
When you're generating passwords, you need to make sure that the passwords are long enough to be secure, but not so long that they're difficult to remember.

Simplified Explanation of ERR_SYNTHETIC

Imagine you want to tell someone all the things that happened when you were playing with your toys. You could just talk to them, but it would be hard for them to picture everything in their head. Instead, you could draw a map of all the steps you took. This map would be artificial, meaning you created it to show what happened, but it would help the person understand what you were doing.

The ERR_SYNTHETIC error is like that map. It's an artificial error object that captures the call stack (a list of all the functions that were called to get to the current point in the code) for diagnostic reports. This call stack helps developers see exactly what was happening when an error occurred, making it easier to find and fix the problem.

Real-World Example

Imagine you're building a website and you want to show a user a list of their friends. You write some code to fetch the list of friends from a database, but there's a problem with the database connection. An ERR_SYNTHETIC error would be thrown, capturing the call stack that shows all the steps the code took to get to that point. This call stack would help the developer see that the error was caused by the database connection issue and fix it.

Applications in the Real World

The ERR_SYNTHETIC error is useful in debugging and troubleshooting code. It can help developers:

Find and fix bugs in their code
Identify the root cause of errors
Improve the performance of their code

ERR_SYSTEM_ERROR

What is it?

A system error is a non-specific error that happens within the Node.js process. It's like when your computer gets confused and doesn't know exactly what went wrong.

How to identify it:

You can identify it by checking the err.info property of the error object. This property will have additional information about the error.

try {
  // Some code that might cause a system error
} catch (err) {
  if (err.code === "ERR_SYSTEM_ERROR") {
    console.error("System error:", err.info);
  }
}

Real-world example:

One potential application of this error is in a file-reading program. If the program tries to read a file that doesn't exist or is corrupted, it might throw a ERR_SYSTEM_ERROR error.

`ERR_TAP_LEXER_ERROR`

This error occurs when the lexer (the part of the compiler that breaks down the code into smaller pieces) encounters an unexpected character or sequence of characters. It's like when you're reading a book and you come across a word you don't know. The lexer is trying to figure out what the code means, but it's stuck because it doesn't recognize something. This error message tells you that the lexer has hit a roadblock and can't continue.

Real-world example:

Imagine you're writing a program to calculate the area of a circle. You tell the program to use the formula area = πr², where π is a constant and r is the radius of the circle. But you accidentally type area = πr^2 instead. The lexer will hit a roadblock when it sees the ^ character because it doesn't understand what it means. The error message will look something like this:

ERR_TAP_LEXER_ERROR: Unexpected character '^'

Potential applications:

This error is useful for debugging code and making sure that it's syntactically correct (follows the rules of the language). It can help you find typos, missing characters, or other syntax errors that might prevent your program from running correctly.

Error: ERR_TAP_PARSER_ERROR

What is it?

The ERR_TAP_PARSER_ERROR error occurs when a parser (a program that checks if the syntax of a code is correct) finds a mistake in the code. The error provides additional details about the token (a unit of code) that caused the issue.

How to fix it?

Check the error message to see which token is causing the problem. Then, examine the code to find any syntax errors or typos. Correct the errors and try running the code again.

Example:

const fs = require("fs");

// Attempt to parse a TAP file with an invalid syntax
fs.readFileSync("invalid_tap_file.tap", "utf8");

// This will throw an ERR_TAP_PARSER_ERROR
// because the TAP file has an incorrect format

Potential applications:

This error is typically encountered when working with TAP (Test Anything Protocol) files. TAP files are used to record test results, and a parser is needed to interpret their contents. If the TAP file has syntax errors, the parser will throw this error.

`ERR_TAP_VALIDATION_ERROR`

This is an error that happens when the Test Anything Protocol (TAP) validation fails. TAP is a protocol used for testing in Node.js. When you write a test in Node.js, you can use the TAP protocol to validate the results of your test. If the validation fails, the ERR_TAP_VALIDATION_ERROR error will be thrown.

In simple terms:

Imagine you're playing a game and you have to follow certain rules. TAP is like the rules of the game. If you don't follow the rules, like if you try to move a piece in a way that's not allowed, the game will give you an error message. ERR_TAP_VALIDATION_ERROR is like that error message. It tells you that you didn't follow the rules of TAP when writing your test.

Code example:

const assert = require("assert");

// Create a test case
assert.ok(true);

// The test case passes, so the validation succeeds

Applications in the real world:

TAP is used in many different testing frameworks in Node.js, such as Mocha and Ava. It helps to ensure that your tests are accurate and reliable.

`ERR_TEST_FAILURE`

Simplified Explanation:

This error happens when a test fails. It's like when you try to solve a puzzle and can't figure it out. The error tells you that the test didn't work.

Additional Information:

cause: This property gives more details about why the test failed. It's like a hint that can help you figure out what went wrong.
failureType: This property tells you what part of the test failed. It's like knowing if you made a mistake in putting the puzzle piece in the right place or if the puzzle piece was broken.

Code Example:

try {
  // This test will fail
  expect(1 + 1).toEqual(3);
} catch (error) {
  // This error will be `ERR_TEST_FAILURE`
  console.error(error.message);
}

Real-World Applications:

Writing automated tests to make sure your code works as expected
Identifying and fixing bugs in your code
Ensuring the quality of your software

Simplified Explanation:

Imagine you're trying to talk to a computer over the internet. The computer supports different "languages" called ALPN protocols. Your computer knows these languages and sends a list to the other computer.

When the other computer tries to talk back, it has to pick one of the languages your computer sent. But if it picks a language that your computer doesn't know, there's a problem.

This error happens when the other computer tries to use a language that your computer doesn't understand. It's like trying to talk to someone in a language they don't speak.

Real-World Implementation:

// Create a list of supported ALPN protocols
const protocols = ["h2", "http/1.1"];

// Create an ALPN callback function
const callback = (protocols) => {
  // Check if the offered protocols are supported
  if (!protocols.some((p) => protocols.includes(p))) {
    throw new Error("ERR_TLS_ALPN_CALLBACK_INVALID_RESULT");
  }

  // Choose the first supported protocol
  return protocols[0];
};

Potential Applications:

Securely transmitting data over the internet
Establishing encrypted connections between web browsers and servers
Improving communication efficiency in web applications

Simplified Explanation of ERR_TLS_ALPN_CALLBACK_WITH_PROTOCOLS:

Imagine your computer is like a door and you want to communicate with another computer securely. To do this, you need a key to unlock the door.

In this case, the key is called a TLS certificate. The certificate allows the other computer to verify that you are who you say you are.

But sometimes, you need to use a special kind of key that can do even more than just unlock the door. This special key is called an ALPN callback.

The ALPN callback can tell the other computer which language you want to use to communicate. Like when you speak English to your friend, you might need to use French to communicate with someone else.

The problem is, if you use both the regular key and the special ALPN key together, the door won't open correctly. That's because they are like two different keys that can't be used at the same time.

So, when you create a TLS server, you can't have both a regular ALPN protocol and an ALPN callback. You need to choose one or the other.

Real-World Example:

Imagine you're building a website that sells shoes. You want to use HTTPS to protect the communication between your website and customers' computers.

To do this, you need to create a TLS server on your website. When you create the server, you need to specify which key you want to use.

If you want to use the regular ALPN protocol, you would write code like this:

const tls = require("tls");

const server = tls.createServer({
  ALPNProtocols: ["http/1.1"],
});

But if you want to use the ALPN callback, you would write code like this:

const tls = require("tls");

const server = tls.createServer({
  ALPNCallback: (socket, protocols, cb) => {
    cb(null, "http/1.1");
  },
});

Potential Applications:

Website security: TLS servers are used to protect the communication between websites and users' computers.
Email encryption: TLS servers are used to encrypt email messages as they are sent and received.
Secure messaging: TLS servers are used to encrypt instant messages and other types of communication.

Error: ERR_TLS_CERT_ALTNAME_FORMAT

This error occurs when you create a TLS certificate using Node.js and provide an invalid value for the subjectAltName property. The subjectAltName property specifies the alternative names that can be used to identify the certificate, such as a domain name or IP address.

Simplified Explanation:

Imagine you have a certificate that says "This certificate is for the website example.com." But you also want people to be able to access the website using the domain name www.example.com. You can add an alternative name to the certificate that says "This certificate is also for www.example.com."

If you try to add an alternative name that isn't formatted correctly, Node.js will throw the ERR_TLS_CERT_ALTNAME_FORMAT error.

Real-World Example:

Let's say you're setting up a website and want to use a TLS certificate to secure it. You create a certificate with the following properties:

subjectAltName: 'example.com'

This certificate will work fine because the alternative name is formatted correctly. However, if you change the alternative name to the following:

subjectAltName: 'www.example.com example.com'

Node.js will throw the ERR_TLS_CERT_ALTNAME_FORMAT error because the alternative names are not separated by a comma.

Potential Applications:

The ERR_TLS_CERT_ALTNAME_FORMAT error can help you identify and fix invalid certificates before you use them to secure your website or application.

Simplified Explanation of ERR_TLS_CERT_ALTNAME_INVALID

When you talk to someone online, you need to know that you're talking to the right person. To make sure, you can check their ID card. In the world of computers, this ID card is called a certificate.

A certificate contains the name of the website or server you're trying to connect to. This name is called the "Subject Alternative Name" (SAN). It's like the name on the ID card.

If the name on the certificate doesn't match the website or server you're trying to connect to, you get an error called ERR_TLS_CERT_ALTNAME_INVALID. It's like the ID card has the wrong name on it.

Example:

Imagine you're trying to connect to the website "www.example.com". You expect the certificate to have the name "www.example.com" in the SAN field. But instead, it has the name "www.hacker.com". This would cause the ERR_TLS_CERT_ALTNAME_INVALID error.

Potential Applications:

This error helps ensure that you're always connecting to the correct website or server. It prevents hackers from pretending to be other websites or servers and stealing your information.

`ERR_TLS_DH_PARAM_SIZE`

Simplified explanation:

When you're using TLS to secure a connection, you're using a mathematical technique called Diffie-Hellman key exchange to agree on a secret key. The size of the numbers used in this process determines how secure the connection is.

Code snippet:

const tls = require("tls");

// Create a TLS server
const server = tls.createServer({
  // Set the DH parameter size to 2048 bits
  dhparam: 2048,
});

Real-world example:

TLS is used to secure many different types of connections, such as:

Web browsing: When you visit a website over HTTPS, TLS is used to encrypt the connection between your browser and the website's server.
Email: When you send or receive an email through a secure email provider, TLS is used to encrypt the connection between your email client and the email server.
Online banking: When you log into your online banking account, TLS is used to encrypt the connection between your web browser and the bank's server.

Potential applications:

TLS is essential for securing any type of connection where privacy and confidentiality are important. Some potential applications include:

E-commerce websites: TLS can be used to protect customer data, such as credit card numbers and addresses.
Healthcare systems: TLS can be used to protect patient data, such as medical records and test results.
Government websites: TLS can be used to protect sensitive government data, such as national security information and intelligence reports.

`ERR_TLS_HANDSHAKE_TIMEOUT`

Imagine two friends trying to shake hands (a handshake is like a special greeting). But one friend is taking too long to get ready, and the other friend gets tired of waiting. So the other friend just gives up on the handshake and goes away.

This is similar to what happens when a computer tries to connect to a website using a special kind of handshake called TLS/SSL. If the website takes too long to get ready for the handshake, the computer will give up and stop trying to connect.

`ERR_TLS_INVALID_CONTEXT`

Imagine a group of friends trying to play a game together. But one friend is using a different set of rules than the other friends. So the game can't start because the rules don't match.

This is similar to what happens when a computer tries to connect to a website using a special protocol called TLS/SSL. If the website and the computer are using different settings for TLS/SSL, the connection can't be established.

Real-World Code Implementation

const https = require("https");

https.get("https://example.com", (res) => {
  console.log("Connected!");
});

Potential Applications

TLS/SSL is used to secure communication between computers, such as when you access a website or send an email. It ensures that the data you send and receive is encrypted and protected from eavesdropping.

ERR_TLS_INVALID_CONTEXT

Explanation:

When trying to establish a secure TLS connection, you must provide a valid SecureContext object. This object contains the necessary certificates and keys for encryption and authentication. If you provide an invalid context, this error is thrown.

Simplified Explanation:

Imagine you're building a secret fort with your friends. To keep intruders out, you need a secret password. If you try to use the wrong password, you won't be able to get into the fort. Similarly, in TLS connections, the SecureContext is like the secret password. If you use the wrong password (invalid context), you won't be able to securely connect to the server.

Real-World Example:

Consider an e-commerce website that uses TLS to protect user data during transactions. When a customer visits the website, their browser sends a request to the server. If the server has a valid SecureContext, the connection between the browser and server is encrypted, ensuring that any sensitive information remains secure.

Code Example:

const https = require("https");

// Create an https server with a valid SecureContext
const server = https.createServer({
  cert: "path/to/certificate.pem",
  key: "path/to/key.pem",
});

server.listen(8443);

In this example, the SecureContext is created using the cert and key options, which specify the location of the server's certificate and private key. With a valid SecureContext, the server can establish secure TLS connections with clients.

Simplified Explanation:

When you try to send data over a secure connection (like when you use a website that starts with "https"), your computer and the website need to agree on how to keep the data safe. They do this by using a protocol, which is like a set of rules for how to do things.

If you choose a protocol that is not known or is not considered safe anymore, your computer will give you this error to let you know that it can't protect the data properly.

Example:

Imagine you want to send a secret message to your friend. You could make up a secret code and use it to write the message. But if you use a very simple code, your friend might be able to guess it and read your message without your permission. To avoid this, you could use a more complicated code that is harder to guess.

Code Snippet:

try {
  // Create a secure connection using an unknown protocol
  const secureSocket = new net.Socket();
  secureSocket.connect(443, "example.com", {
    secureProtocol: "unknown-protocol",
  });
} catch (err) {
  // Handle the error (ERR_TLS_INVALID_PROTOCOL_METHOD)
}

Potential Applications:

Secure communication between websites and users
Sending sensitive information over the internet
Protecting online transactions

`ERR_TLS_INVALID_PROTOCOL_VERSION`

When creating a TLS socket, you must specify a valid TLS protocol version. For example:

const tls = require("tls");

const socket = tls.connect({
  host: "example.com",
  port: 443,

  // Specify the TLS protocol version
  secureProtocol: "TLSv1_2_method",
});

If you specify an invalid protocol version, you will get the ERR_TLS_INVALID_PROTOCOL_VERSION error.

Valid TLS protocol versions are:

'TLSv1'
'TLSv1.1'
'TLSv1.2'

`ERR_TLS_INVALID_STATE`

The ERR_TLS_INVALID_STATE error is thrown when a TLS socket is in an invalid state. For example, the socket may be in the 'connecting' state and you try to send data on it.

To fix this error, you must ensure that the TLS socket is in a valid state before performing any operations on it. You can check the state of the socket using the socket.readyState property.

Valid TLS socket states are:

'closed'
'connecting'
'open'

Real-World Applications

TLS is used to secure communications between two computers. For example, TLS is used to secure web traffic (HTTPS) and email (SMTP).

By using TLS, you can ensure that the data you send and receive is encrypted and cannot be intercepted or tampered with.

Potential Applications

TLS can be used to secure any type of communication between two computers. Here are a few examples:

Web traffic (HTTPS)
Email (SMTP)
File transfers (FTP)
Remote desktop (RDP)
Virtual private networks (VPNs)

`ERR_TLS_INVALID_STATE`

Imagine you have a secret door that only opens when you have a special key. This special key is called a "certificate".

When you want to use the secret door (TLS socket), you first need to connect to the door. Once you're connected, you need to show the special key (certificate) to the door, so that the door can verify that you're allowed to use it.

Only after the door has verified your key, can you open the secret door and securely pass through it.

But if you try to open the door before you've connected to it, or before you've shown the special key, the door won't open, and you'll get an error message saying "Invalid State".

Simplified Code Example:

const tls = require("tls");

const socket = tls.connect(443, "example.com", {
  rejectUnauthorized: false,
});

socket.once("secure", () => {
  // The secret door is now open and secure!
});

socket.on("error", (err) => {
  if (err.code === "ERR_TLS_INVALID_STATE") {
    console.log("Oops, you forgot to connect or show the special key!");
  }
});

Potential Applications:

Secure communication between servers and clients, such as in online banking or e-commerce.
Encrypting data in transit, such as sensitive medical records or financial information.

ERR_TLS_PROTOCOL_VERSION_CONFLICT

Explanation:

Imagine you're having a secret conversation with your friend using a special code. This code is like a set of rules for how to talk to each other secretly.

Now, you want to change these rules. But you've also told your friend to use a different, specific code. This is like telling someone to use a secret code, but then also giving them another specific code to use.

Simplified example:

// Trying to set both `minVersion` and `secureProtocol`
const tlsOptions = {
  minVersion: 'TLSv1.2',
  secureProtocol: 'TLSv1.3',
};

ERR_TLS_PSK_SET_IDENTIY_HINT_FAILED

Explanation:

Imagine you're sending a secret message to your friend using a pre-shared key (PSK). This PSK is like a password that you both know.

You want to add a hint to your message, which is like a clue that helps your friend find the message. But somehow, this hint can't be set up properly. This error means that the PSK identity hint couldn't be set.

Simplified example:

// Trying to set a PSK identity hint
const pskOptions = {
  psk: '123456',
  identityHint: 'top secret',
};

Real-world applications:

Secure communications: TLS is used to protect data sent over the internet, such as online banking and email.
Authentication: TLS can be used to verify the identity of a server or client.
PSK-based authentication: PSK can be used to authenticate users without the need for passwords, which can be more secure.

Potential applications:

E-commerce websites using TLS to protect customer data during online transactions.
Email providers using TLS to ensure the privacy and security of emails.
Mobile banking apps using PSK to provide secure and convenient authentication.

Previousevents Nextglobals

Errors in Node.js

Error(message, options)

Potential applications

Error.captureStackTrace(targetObject[, constructorOpt])

Error.stackTraceLimit Explained for a 5-Year-Old Child

What is an error code?

Why are error codes important?

How do I use error codes?

What are some common error codes?

How can I find out more about error codes?

Real-world example

Potential applications

Error.message property

Real-world applications

error.address

Real-world example

Potential applications

Error: TypeError

What is TypeError?

Simplified Explanation:

Real-World Example:

Applications in the Real World:

error.opensslErrorStack

Node.js Error Codes

Real-World Examples

Potential Applications

Conclusion

Error: Access Denied (ERR_ACCESS_DENIED)

Applications in the Real World:

ERR_ASSERTION

ERR_ASYNC_CALLBACK

Real-world Example

Potential Applications

ERR_ASYNC_TYPE

Real-world applications

Potential applications

ERR_BROTLI_COMPRESSION_FAILED

Simplified Explanation

Real-World Code Example

Potential Applications

ERR_BUFFER_TOO_LARGE

ERR_CHILD_CLOSED_BEFORE_REPLY

ERR_CHILD_PROCESS_IPC_REQUIRED

Real-world applications

ERR_CLOSED_MESSAGE_PORT

ERR_CONSTRUCT_CALL_INVALID

ERR_CONSTRUCT_CALL_REQUIRED

ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED

Real-World Example:

Potential Applications:

ERR_CRYPTO_ENGINE_UNKNOWN

ERR_CRYPTO_HASH_FINALIZED

Real-World Example

Potential Applications

Simplified Explanation

Code Snippet

Real-World Applications

Simplified Explanation of ERR_CRYPTO_INCOMPATIBLE_KEY Error

ERR_CRYPTO_INCOMPATIBLE_KEY_OPTIONS

ERR_CRYPTO_INITIALIZATION_FAILED

Real-World Applications

Code Implementations

Simplified Explanation of ERR_CRYPTO_INVALID_CURVE

Real-World Example

Potential Applications

Simplified Explanation of ERR_CRYPTO_INVALID_DIGEST

Real-World Example

Potential Applications

ERR_CRYPTO_INVALID_KEYPAIR

ERR_CRYPTO_INVALID_KEYTYPE

ERR_CRYPTO_INVALID_MESSAGELEN

ERR_CRYPTO_INVALID_SCRYPT_PARAMS

ERR_CRYPTO_INVALID_STATE

ERR_CRYPTO_JOB_INIT_FAILED

ERR_CRYPTO_JWK_UNSUPPORTED_CURVE

Simplified Explanation of ERR_CRYPTO_JWK_UNSUPPORTED_KEY_TYPE

Real World Example

Code Example

Potential Applications

ERR_CRYPTO_SCRYPT_INVALID_PARAMETER

`Error.captureStackTrace(targetObject[, constructorOpt])`

`Error.stackTraceLimit` Explained for a 5-Year-Old Child

`error.address`

`error.opensslErrorStack`

`ERR_ASSERTION`

`ERR_ASYNC_CALLBACK`

`ERR_ASYNC_TYPE`

`ERR_BROTLI_COMPRESSION_FAILED`

`ERR_BUFFER_TOO_LARGE`

`ERR_CHILD_CLOSED_BEFORE_REPLY`

`ERR_CHILD_PROCESS_IPC_REQUIRED`

`ERR_CLOSED_MESSAGE_PORT`

`ERR_CONSTRUCT_CALL_INVALID`

`ERR_CONSTRUCT_CALL_REQUIRED`

`ERR_CRYPTO_CUSTOM_ENGINE_NOT_SUPPORTED`

`ERR_CRYPTO_ENGINE_UNKNOWN`

`ERR_CRYPTO_HASH_FINALIZED`

Simplified Explanation of `ERR_CRYPTO_INCOMPATIBLE_KEY` Error

`ERR_CRYPTO_INCOMPATIBLE_KEY_OPTIONS`

`ERR_CRYPTO_INITIALIZATION_FAILED`

Simplified Explanation of `ERR_CRYPTO_INVALID_CURVE`

`ERR_CRYPTO_INVALID_KEYPAIR`

`ERR_CRYPTO_INVALID_KEYTYPE`

`ERR_CRYPTO_INVALID_MESSAGELEN`

`ERR_CRYPTO_INVALID_SCRYPT_PARAMS`

`ERR_CRYPTO_INVALID_STATE`

`ERR_CRYPTO_JOB_INIT_FAILED`

`ERR_CRYPTO_JWK_UNSUPPORTED_CURVE`

Simplified Explanation of `ERR_CRYPTO_JWK_UNSUPPORTED_KEY_TYPE`

`ERR_CRYPTO_SCRYPT_INVALID_PARAMETER`

`ERR_CRYPTO_SCRYPT_NOT_SUPPORTED`

`ERR_CRYPTO_SCRYPT_NOT_SUPPORTED`

`ERR_CRYPTO_UNSUPPORTED_OPERATION` Error

`ERR_DLOPEN_DISABLED`

`ERR_DLOPEN_FAILED`

`ERR_DLOPEN_FAILED`

`ERR_DIR_CLOSED`

`ERR_DIR_CONCURRENT_OPERATION`

Simplified Explanation of `ERR_DOMAIN_CALLBACK_NOT_AVAILABLE`

`ERR_DOMAIN_CANNOT_SET_UNCAUGHT_EXCEPTION_CAPTURE`

`ERR_DUPLICATE_STARTUP_SNAPSHOT_MAIN_FUNCTION`

Simplified Explanation of `ERR_EVENT_RECURSION`

Simplified Explanation of `ERR_EXECUTION_ENVIRONMENT_NOT_AVAILABLE`

`ERR_FALSY_VALUE_REJECTION`

`ERR_FS_CP_DIR_TO_NON_DIR`

`ERR_FS_CP_SYMLINK_TO_SUBDIRECTORY`

`ERR_HTTP_INVALID_HEADER_VALUE` error simplified

`ERR_HTTP_SOCKET_ENCODING`

`ERR_HTTP_TRAILER_INVALID`

`ERR_HTTP_TRAILER_INVALID`

`ERR_HTTP2_ALTSVC_INVALID_ORIGIN`

`ERR_HTTP2_ALTSVC_LENGTH`

`ERR_HTTP2_CONNECT_SCHEME`

`ERR_HTTP2_HEADERS_AFTER_RESPOND`

`ERR_HTTP2_HEADERS_SENT`

`ERR_HTTP2_INVALID_CONNECTION_HEADERS`

`ERR_HTTP2_INVALID_PACKED_SETTINGS_LENGTH`

`ERR_HTTP2_INVALID_SESSION` Explained

`ERR_HTTP2_INVALID_STREAM`

Simplified Explanation of `ERR_HTTP2_MAX_PENDING_SETTINGS_ACK`

`ERR_HTTP2_NO_MEM`

`ERR_HTTP2_ORIGIN_LENGTH`

`ERR_HTTP2_OUT_OF_STREAMS`

`ERR_HTTP2_PUSH_DISABLED`