How can I replace every instance of a string in JavaScript

Question

In the JS interview, I was facing an issue related to an instance of a string, so can you tell me How I can replace every instance of a string in JavaScript?

Answer 1

In JavaScript, replacing all instances of a substring within a string can be achieved using several methods:

1. Using String.prototype.replaceAll():

const originalString = 'Hello world! Hello universe!';

const newString = originalString.replaceAll('Hello', 'Hi');

console.log(newString); // Output: 'Hi world! Hi universe!'

Note: replaceAll() is part of ECMAScript 2021 and may not be supported in all environments. Ensure compatibility or consider using a polyfill if targeting older environments.

2. Using String.prototype.replace() with a Global Regular Expression:

const originalString = 'Hello world! Hello universe!';

const newString = originalString.replace(/Hello/g, 'Hi');

console.log(newString); // Output: 'Hi world! Hi universe!'

In this example, the regular expression /Hello/g matches all occurrences of 'Hello'. The replace() method then replaces each match with 'Hi'.