util

---

1. Error Handling with try/catch

try {
  // Code that may throw an error
} catch (error) {
  // Error handling code
}

2. Iterating Over Objects with for...in

const obj = { a: 1, b: 2, c: 3 };

for (const key in obj) {
  console.log(`${key}: ${obj[key]}`);
}

3. Array Reduction with reduce()

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

const sum = numbers.reduce((total, value) => total + value, 0);

4. Converting a String to a Number with parseInt()

const numStr = "123";

const num = parseInt(numStr);

5. Converting a String to a Floating-Point Number with parseFloat()

const numStr = "123.45";

const num = parseFloat(numStr);

6. Array Filtering with filter()

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

const evens = numbers.filter(num => num % 2 === 0);

7. Array Mapping with map()

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

const doubles = numbers.map(num => num * 2);

8. Creating a Promise

const promise = new Promise((resolve, reject) => {
  // Promise logic
});

9. Using Promise.all()

const promise1 = Promise.resolve(1);
const promise2 = Promise.resolve(2);

Promise.all([promise1, promise2]).then(values => {
  // Use the values
});

10. Using Promise.race()

const promise1 = new Promise(resolve => {
  setTimeout(() => resolve(1), 1000);
});
const promise2 = new Promise(resolve => {
  setTimeout(() => resolve(2), 500);
});

Promise.race([promise1, promise2]).then(value => {
  // Use the value
});

11. Creating a Buffer

const buffer = Buffer.from("Hello world");

12. Writing Data to a Buffer

const buffer = Buffer.alloc(10);

buffer.write("Hello world");

13. Reading Data from a Buffer

const buffer = Buffer.from("Hello world");

const data = buffer.toString();

14. Converting a Buffer to Base64

const buffer = Buffer.from("Hello world");

const base64 = buffer.toString("base64");

15. Creating a Cryptographically Secure Random String

const crypto = require("crypto");

const randomStr = crypto.randomBytes(16).toString("hex");

16. Hashing Data with SHA256

const crypto = require("crypto");

const hash = crypto.createHash("sha256").update("Hello world").digest("hex");

17. Reading a File with fs.readFile()

const fs = require("fs");

fs.readFile("file.txt", "utf8", (err, data) => {
  // Use the data
});

18. Creating a Readable Stream

const fs = require("fs");

const stream = fs.createReadStream("file.txt");

19. Creating a Writable Stream

const fs = require("fs");

const stream = fs.createWriteStream("file.txt");

20. Piping a Stream

const fs = require("fs");

const readStream = fs.createReadStream("file.txt");
const writeStream = fs.createWriteStream("file-copy.txt");

readStream.pipe(writeStream);

21. Reading from a Pipe with pipe()

const process = require("process");

process.stdout.pipe(process.stdin);

22. Sending Data to a Pipe with unpipe()

const process = require("process");

process.stdin.unpipe(process.stdout);

23. Creating a Timeout Function

setTimeout(() => {
  // Code to execute after timeout
}, 1000);

24. Creating an Interval Function

setInterval(() => {
  // Code to execute every interval
}, 1000);

25. Creating a Promise Queue with async.queue() from "async"

const async = require("async");

const queue = async.queue((task, callback) => {
  // Task to perform
  callback();
}, 1);

26. Throttling Functions with async.throttle() from "async"

const async = require("async");

const throttledFn = async.throttle(fn, 1000);

27. Memoizing Functions with memoize() from "lodash"

const _ = require("lodash");

const memoizedFn = _.memoize(fn);

28. Currying Functions with curry() from "lodash"

const _ = require("lodash");

const curriedFn = _.curry(fn);

29. Debouncing Functions with debounce() from "lodash"

const _ = require("lodash");

const debouncedFn = _.debounce(fn, 1000);

30. Cloning an Object with cloneDeep() from "lodash"

const _ = require("lodash");

const clone = _.cloneDeep(obj);

31. Merging Objects with merge() from "lodash"

const _ = require("lodash");

const mergedObj = _.merge(obj1, obj2);

32. Generating a Unique ID with shortid() from "shortid"

const shortid = require("shortid");

const id = shortid.generate();

33. Validating an Email Address with validate() from "validator"

const validator = require("validator");

const isValid = validator.isEmail("[e-mail]");

34. Normalizing a String with normalize() from "normalize-string"

const normalize = require("normalize-string");

const normalizedStr = normalize("Hello world");

35. Sanitizing HTML with sanitizeHtml() from "sanitize-html"

const sanitize = require("sanitize-html");

const sanitizedHtml = sanitize.sanitizeHtml("<script>alert('XSS')</script>");

36. Formatting Dates with formatDistanceToNowStrict() from "date-fns"

const dateFns = require("date-fns");

const formattedDate = dateFns.formatDistanceToNowStrict(new Date(), { addSuffix: true });