JavaScript Tips and Tricks - JavaScript Job Interview Questions

by MD Hasan Patwary

HTML

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>JavaScript Tips & Tricks</title>
  </head>
  <body>
    <h1>২ হালি JavaScript Tips</h1>
    <!-- <p id="text">learnwithsumit.com</p>
    <p><button id="copy" onclick="handleClick()">Copy</button></p> -->
    <!-- <input id="number" type="number" value="123" /> -->
    <script src="./main.js"></script>
  </body>
</html>

JavaScript

// 1. Swaping values
let array = [1, 2, 3, 4, 5];

// temp variable
// let temp = array[0];
// array[0] = array[4];
// array[4] = temp;

// console.log(array);

// array destructuring
// [array[0], array[4]] = [array[4], array[0]];
// console.log(array);

let a = 1;
let b = 2;
// [a, b] = [b, a];
// console.log(a, b);

// math
b = a + (a = b) - b;
console.log(a, b);



// 2. copy to clipboard

function copyToClipBoard(str) {
  const element = document.createElement("textarea");
  element.value = str;
  document.body.appendChild(element);
  element.select();
  document.execCommand("copy");
  document.body.removeChild(element);
}

function handleClick() {
  let text = document.querySelector("#text");
  copyToClipBoard(text.innerText);
}

// 3. destructuring aliases

const language = {
  name: "JavaScript",
  founded: 1995,
  founder: "Brendan Eich",
};

const { name: languageName, founder: createrName } = language;

console.log(languageName, createrName);


// 4. get value as data type

const element = document.querySelector("#number").valueAsNumber;

console.log(typeof element);


// 5. remove duplicates from array
const array = [1, 2, 2, 2, 3, 5, 6, 5];

console.log([...new Set(array)]);


// 6. compare two arrays by value
const hasSameElements = (a, b) => {
  return a.length === b.length && a.every((v, i) => v === b[i]);
};

console.log(hasSameElements([1, 2], [1, 2]));

// 7. shuffling array
const numbers = [1, 2, 3, 4, 5, 6];

console.log(numbers.sort(() => Math.random() - 0.5));

// 8. comma operator

let x = 1;
x = (x++, x);

console.log(x);

let y = (2, 3);
console.log(y);

let a = [[1, 2, 3, 4], [3, 4, 5], [5, 6], [7]];

for (let i = 0, j = 3; i <= 3; i++, j--) {
  console.log("a[" + i + "][" + j + "] = " + a[i][j]);
}