20 Most Useful JavaScript Snippets

Enhance your coding efficiency with these essential snippets.

1. Generating a Random Number

let randomNum = Math.floor(Math.random() * maxNum);

2. Checking If an Object is Empty

function isEmptyObject(obj) { return Object.keys(obj).length === 0; }

3. Creating a Countdown Timer

function countdownTimer(minutes) { /* countdown logic */ }

4. Sorting an Array of Objects

function sortByProperty(arr, property) { return arr.sort((a, b) => (a[property] > b[property]) ? 1 : -1); }

5. Removing Duplicates from an Array

let uniqueArr = [...new Set(arr)];

6. Truncating a String

function truncateString(str, num) { return str.length > num ? str.slice(0, num) + "..." : str; }

7. Converting a String to Title Case

function toTitleCase(str) { return str.replace(/\b\w/g, function(txt) { return txt.charAt(0).toUpperCase() + txt.substr(1).toLowerCase(); }); }

8. Checking If a Value Exists in an Array

let isValueInArray = arr.includes(value);

9. Reversing a String

let reversedStr = str.split("").reverse().join("");

10. Creating a New Array from an Existing Array

let newArr = oldArr.map(function(item) { return item + 1; });

11. Debouncing Function Calls

function debounce(func, delay) { let timeout; return function(...args) { clearTimeout(timeout); timeout = setTimeout(() => func.apply(this, args), delay); }; }

12. Throttling Function Calls

function throttle(func, limit) { let lastFunc; let lastRan; return function(...args) { if (!lastRan) { func.apply(this, args); lastRan = Date.now(); } else { clearTimeout(lastFunc); lastFunc = setTimeout(function() { if ((Date.now() - lastRan) >= limit) { func.apply(this, args); lastRan = Date.now(); } }, limit - (Date.now() - lastRan)); } }; }

13. Cloning an Object

const cloneObject = (obj) => ({ ...obj });

14. Merging Two Objects

const mergeObjects = (obj1, obj2) => ({ ...obj1, ...obj2 });

15. Checking for Palindrome Strings

function isPalindrome(str) { const cleanedStr = str.replace(/[^A-Za-z0-9]/g, '').toLowerCase(); return cleanedStr === cleanedStr.split('').reverse().join(''); }

16. Counting Occurrences in an Array

const countOccurrences = (arr) => arr.reduce((acc, val) => (acc[val] ? acc[val]++ : acc[val] = 1, acc), {});

17. Getting the Day of the Year from a Date Object

const dayOfYear = date => Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);

18. Filtering Unique Values from an Array

const uniqueValues = arr => [...new Set(arr)];

19. Converting Degrees to Radians

const degreesToRads = deg => (deg * Math.PI) / 180;

20. Delaying Function Execution

const defer = (fn, ...args) => setTimeout(fn, 1, ...args);