18 killer JavaScript one-liners

Preface

JavaScript continues to grow and prosper because it is one of the easiest languages ​​to pick up, thus opening the door for new tech geeks in the market.

And, whether you’re new to JavaScript or a more of a professional developer, learning something new is always a good thing.

This article has compiled some very useful one-liners that can help you improve your work efficiency.

What is a one-line code?

One-liners are a coding practice where we perform some functionality with just one line of code.

One-line code example

1. Copy to clipboard

Use navigator.clipboard.writeText to easily copy any text to the clipboard.

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

2. Check if the date is valid

Use the following code snippet to check whether a given date is valid or not.

const isDateValid = (...val) => !Number.isNaN(new Date(...val).valueOf());
isDateValid("December 17, 1995 03:24:00");
// Result: true

3. Find out the day of the year

Find the day of a given date.

const dayOfYear = (date) => Math.floor((date - new Date(date.getFullYear(), 0, 0)) / 1000 / 60 / 60 / 24);
dayOfYear(new Date());
// Result: 272

4. Capitalize the first string

Javascript does not have a built-in uppercase function, so we can use the following code.

const capitalize = str => str.charAt(0).toUpperCase() + str.slice(1)capitalize("follow for more") // Result: Follow for more

5. Find the number of days between two dates

Use the following code snippet to find the number of days between the given 2 dates.

const dayDif = (date1, date2) => Math.ceil(Math.abs(date1.getTime() - date2.getTime()) / 86400000)dayDif(new Date("2020-10-21"), new Date("2021-10-22"))// Result: 366

6. Clear all cookies

You can easily clear all cookies stored in a web page by accessing the cookies using document.cookie and clearing it.

const clearCookies = document.cookie.split(';').forEach(cookie => document.cookie = cookie.replace(/^ +/, '')
.replace(/=.*/, `=;expires=${new Date(0).toUTCString()};
path=/`));

7. Generate random hexadecimal

You can use Math.random and the padEnd property to generate random hexadecimal colors.

const randomHex = () => `#${Math.floor(Math.random() * 0xffffff).toString(16).padEnd(6, "0")}`
console.log(randomHex());
//Result: #92b008

8. Remove duplicates from an array

You can easily remove duplicates using Set in JavaScript.

const removeDuplicates = (arr) => [...new Set(arr)];
console.log(removeDuplicates([1, 2, 3, 3, 4, 4, 5, 5, 6]));
// Result: [ 1, 2, 3, 4, 5, 6 ]

9. Get query parameters from URL

You can retrieve query parameters from the url easily by passing window.location or the original URL goole.com?search=easy&page=3

const getParameters = (URL) => {
 URL = JSON.parse('{"' + decodeURI(URL.split("?")[1]).replace(/"/g, '\"').replace(/&/g, '","').replace(
 /=/g, '":"') + '"}');
 return JSON.stringify(URL);
};
getParameters(window.location) // Result: { search : "easy", page : 3 }

10. Record time from date

We can record the time in the format hours::minutes::seconds from a given date.

const timeFromDate = date => date.toTimeString().slice(0, 8);
console.log(timeFromDate(new Date(2021, 0, 10, 17, 30, 0))); 
// Result: "17:30:00"

11. Check if a number is even or odd

const isEven = num => num % 2 === 0; console.log(isEven(2));
 // Result: True

12. Find the average of numbers

Use the reduce method to find the average between multiple numbers.

const average = (...args) => args.reduce((a, b) => a + b) / args.length;
average(1, 2, 3, 4);
// Result: 2.5

13. Reverse a string

You can easily reverse a string using the split, reverse, and join methods.

const reverse = str => str.split('').reverse().join('');reverse('hello world'); 
// Result: 'dlrow olleh'

14. Check if the array is empty

A simple one-liner that checks if an array is empty will return true or false.

const isNotEmpty = arr => Array.isArray(arr) && arr.length > 0;
isNotEmpty([1, 2, 3]);
// Result: true

15. Get the selected text

Use the built-in getSelectionproperty to get the text selected by the user.

const getSelectedText = () => window.getSelection().toString();
getSelectedText();

16. Shuffle the array

It is very easy to shuffle an array using the sort and random methods.

const shuffleArray = (arr) => arr.sort(() => 0.5 - Math.random()); console.log(shuffleArray([1, 2, 3, 4])); // Result: [ 1, 4, 3, 2 ]

17. Detect dark mode

Use the following code to check if the user's device is in dark mode.

const isDarkMode = window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matchesconsole.log(isDarkMode) // Result: True or False

18. Convert RGB to Hexadecimal

const rgbToHex = (r, g, b) => "#" + ((1 << 24) + (r << 16) + (g << 8) + b).toString(16).slice(1);rgbToHex(0, 51, 255); // Result: #0033ff

Summarize

This is the end of this article about JavaScript one-line code. For more relevant JavaScript one-line code content, please search for previous articles on 123WORDPRESS.COM or continue to browse the following related articles. I hope everyone will support 123WORDPRESS.COM in the future!