const reversedString = str => str.split('').reverse().join('');reversedString("Hello World"); // dlroW olleH

const titleCase = sentence => sentence.replace(/\b\w/g, char => char.toUpperCase());titleCase("hello world"); // Hello World

[a, b] = [b, a];

const isTruthy = num => !!num;isTruthy(0) // False

const uniqueArray = arr => [...new Set(arr)];uniqueArray([5,5,2,2,2,4,2]) // [ 5, 2, 4 ]

const truncateString = (str, maxLength) => (str.length > maxLength) ? `${str.slice(0, maxLength)}...` : str;truncateString("Hello World", 8); // Hello Wo...

const deepClone = obj => JSON.parse(JSON.stringify(obj));

const obj1 = { name: "John", age: 40};const obj2 = deepClone(obj1);obj2.age = 20;console.log(obj1.age); // 40//This method works for most objects, but it has some limitations. Objects with circular references or functions cannot be converted to JSON, so this method will not work for those types of objects.

const lastIndexOf = (arr, item) => arr.lastIndexOf(item);lastIndexOf([5, 5, 4 , 2 , 3 , 4], 5) // 1

const mergeArrays = (...arrays) => [].concat(...arrays);mergeArrays([5, 5, 4], [2 , 3 , 4]) // [5, 5, 4, 2, 3, 4]

const longestWord = sentence => sentence.split(' ').reduce((longest, word) => word.length > longest.length ? word : longest, '');longestWord("The quick brown fox jumped over the lazy dog") // jumped

const range = (start, end) => [...Array(end - start + 1)].map((_, i) => i + start);range(5, 15); // [5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

const isEmptyObject = obj => Object.keys(obj).length === 0;isEmptyObject({}) // trueisEmptyObject({ name: 'John' }) // false

const average = arr => arr.reduce((acc, num) => acc + num, 0) / arr.length;average([1, 2, 3, 4, 5, 6, 7, 8, 9]) // 5

const objectToQueryParams = obj => Object.entries(obj).map(([key, val]) => `${encodeURIComponent(key)}=${encodeURIComponent(val)}`).join('&');objectToQueryParams({ page: 2, limit: 10 }) // page=2&limit=10

const factorial = num => num <= 1 ? 1 : num * factorial(num - 1);factorial(4) // 24

const countVowels = str => (str.match(/[aeiou]/gi) || []).length;countVowels('The quick brown fox jumps over the lazy dog') // 11

const isValidEmail = email => /^[\w-]+(\.[\w-]+)*@([\w-]+\.)+[a-zA-Z]{2,7}$/.test(email);isValidEmail("example@email.com") // trueisValidEmail("example") // false

const removeWhitespace = str => str.replace(/\s/g, '');removeWhitespace("H el l o") // Hello

const isLeapYear = year => (year % 4 === 0 && year % 100 !== 0) || (year % 400 === 0);isLeapYear(2023) // falseisLeapYear(2004) // true

const generateRandomString = length => [...Array(length)].map(() => Math.random().toString(36)[2]).join('')generateRandomString(8) // 4hq4zm7y

const copyToClipboard = (content) => navigator.clipboard.writeText(content)copyToClipboard("Hello World")

const currentTime = () => new Date().toLocaleTimeString([], { hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false })currentTime() // 19:52:21

const isEven = num => num % 2 === 0isEven(1) // falseisEven(2) // true

const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matchesconsole.log(isDarkMode) // false

const goToTop = () => window.scrollTo(0, 0)goToTop()

const isValidDate = date => date instanceof Date && !isNaN(date);isValidDate(new Date("This is not date.")) // falseisValidDate(new Date("08-10-2023")) // true

const generateDateRange = (startDate, endDate) => Array.from({ length: (endDate - startDate) / (24 * 60 * 60 * 1000) + 1 }, (_, index) => new Date(startDate.getTime() + index * 24 * 60 * 60 * 1000));generateDateRange(new Date("2023-09-31"), new Date("2023-10-08")) // [Sun Oct 01 2023 05:30:00 GMT+0530 (India Standard Time), Mon Oct 02 2023 05:30:00 GMT+0530 (India Standard Time), Tue Oct 03 2023 05:30:00 GMT+0530 (India Standard Time), Wed Oct 04 2023 05:30:00 GMT+0530 (India Standard Time), Thu Oct 05 2023 05:30:00 GMT+0530 (India Standard Time), Fri Oct 06 2023 05:30:00 GMT+0530 (India Standard Time), Sat Oct 07 2023 05:30:00 GMT+0530 (India Standard Time), Sun Oct 08 2023 05:30:00 GMT+0530 (India Standard Time)]

const areArraysEqual = (arr1, arr2) => JSON.stringify(arr1) === JSON.stringify(arr2);areArraysEqual([1, 2, 3], [4, 5, 6]) // falseareArraysEqual([1, 2, 3], [1, 2, 3]) // false