Here are 20 useful JavaScript snippets that can help you when working on your projects:

1. Get current date and time:

const now = new Date();

2. Check if a variable is an array:

Array.isArray(variable);

3. Merge two arrays:

const newArray = array1.concat(array2);

4. Remove duplicates from an array:

const uniqueArray = [...new Set(array)];

5. Sort an array in ascending order:

array.sort((a, b) => a - b);

6. Reverse an array:

array.reverse();

7. Convert string to number:

const number = parseInt(string);

8. Generate a random number between two values:

const randomNumber = Math.floor(Math.random() * (max - min + 1)) + min;

9. Check if a string contains a substring:

string.includes(substring);

10. Get the length of an object:

Object.keys(object).length;

11. Convert object to array:

const array = Object.entries(object);

12. Check if an object is empty:

((typeof object)=="object") && Object.keys(object).length==0;

13. Get current URL:

const currentUrl = window.location.href;

14. Redirect to a new URL:

window.location.replace(url);

15. Set a cookie:

document.cookie = "name=value; expires=date; path=path; domain=domain; secure";

16. Get a cookie:

const cookieValue = document.cookie.replace(/(?:(?:^|.*;\s*)name\s*\=\s*([^;]*).*$)|^.*$/, "$1");

17. Check if a cookie exists:

document.cookie.split(';').some((item) => item.trim().startsWith('name='))

18. Remove a cookie:

document.cookie = "name=; expires=Thu, 01 Jan 1970 00:00:00 UTC; path=path; domain=domain; secure";

19. Get the current viewport dimensions:

const viewportWidth = Math.max(document.documentElement.clientWidth || 0, window.innerWidth || 0);
const viewportHeight = Math.max(document.documentElement.clientHeight || 0, window.innerHeight || 0);

20. Copy text to clipboard:

navigator.clipboard.writeText(text);

These JavaScript snippets can help save time and simplify your code when working on web projects.