25 JavaScript One-Liner that will help you code like a pro 🎯 !!

3 min readDec 16, 2023

JavaScript is most used language in the internet. Being a developer it will be useful to know the tricks which will ease the coding. So lets check some of the one liner snippets.

We have categorized these one liners snippets based on functionality such as Array, date, Random, Validation, Web Utilities etc.

Array 🌈

1. Check if a variable is an Array

const isArray = Array.isArray(arr);
const isArray = arr instanceof Array;

2. Sum of an Array of Number

const sum = (arr) => arr.reduce((a, b) => a + b);

3. Remove Falsy value from Array

const removeFalsyValues = (arr) => arr.filter(x => x);
// or 
const removeFalsyValues = (arr) => arr.filter(Boolean);

4. Average of an Array of Number

const average = (arr) => arr.reduce((a, b) => a + b) / arr.length;

5. Merge and Remove the Duplications

const merge = (arr1, arr2) => [...new Set(arr1.concat(arr2))];
// or
const merge = (arr1, arr2) => [...new Set([...arr1, ...arr2])];

6. Merge two Arrays

const merge = (arr1, arr2) => [].concat(arr1, arr2);
// or
const merge = (arr1, arr2) => [...arr1, ...arr2];

7. Shuffle an Array

const shuffle = (arr) => arr.slice().sort(() => Math.random() - 0.5);

8. Get the Last Element from an Array

const lastElement = (arr) => arr[arr.length-1];
// or
const lastElement = (arr) => arr.slice(-1)[0];
// or
const lastElement = (arr) => arr.slice().pop();

9. Find Unique Values in an Array

const findUniqueValues = (arr) => arr.filter((i) => arr.indexOf(i) === arr.lastIndexOf(i));

10. Clone an Array

const clone = (arr) => arr.slice();
// or
const clone = (arr) => [...arr];

String 🏐

11. Capitalize a String

const capitalize = (str) => str.charAt(0).toUpperCase() + str.slice(1);

12. String Reverse

const reverseString = (str) => str.split("").reverse().join("");
// or
const reverseString = (str) => [...str].reverse().join();

13. Convert a String to a Number

const toNumber = (str) => Number(str);
// or
const toNumber = (str) => +str;

14. Convert a String to a Character Array

const toCharArray = (str) => str.split('');
// or
const toCharArray = (str) => [...str];
// or
const toCharArray = (str) => Array.from(str);
// or
const toCharArray = (str) => Object.assign([], str);

15. Convert Snake case to Camel case

const snakeToCamel = (str) => str.toLowerCase().replace(/(_\w)/g, (word) => word.toUpperCase().substr(1));

Date 📅

16. Days between two dates

const daysBetweenDates = (date1, date2) => Math.ceil(Math.abs(date1 - date2) / (1000 * 60 * 60 * 24));

17. Weekday of a Date

const getWeekday = (date) => ['Sunday','Monday','Tuesday','Wednesday','Thursday','Friday','Saturday'][date.getDay()];
// or 
const getWeekday = (date) => date.toLocaleString('en-US', {weekday: 'long'});

Random 🎲

18. Random Number Generator

const randomNumber = (rangeStart, rangeEnd) => new Date().getTime() % rangeEnd + rangeStart;
// or
const randomNumber = (min, max) => Math.floor(Math.random() * (max - min + 1) + min);

19. Random Hexadecimal Color Generator

const randomHexColor = () => `#${Math.random().toString(16).slice(2, 8).padEnd(6, '0')}`;

20. Random Boolean Generator

const randomBoolean = () => Math.random() >= 0.5;

Validation ✅

21. Check if an Array Is Empty

const isEmpty = (arr) => !Array.isArray(arr) || !arr.length;

22. Check if Array includes a Value

const includes = (arr, value) => arr.indexOf(value) != -1;
// or
const includes = (arr, value) => arr.includes(value);

23. Check if the date is Weekend

const isWeekend = (date) => [5, 6].indexOf(date.getDay()) !== -1;

Web Utilities 🌐

24. Copy to Clipboard

const copyToClipboard = (text) =>
  navigator.clipboard?.writeText && navigator.clipboard.writeText(text);

// Testing
copyToClipboard("Hello World!");

25. Detect dark mode

const isDarkMode = () =>
  window.matchMedia &&
  window.matchMedia("(prefers-color-scheme: dark)").matches;

// Testing
console.log(isDarkMode());

These snippets will help you write more cleaner code and organize the functionality in less time.

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