In this post, I'll share two ways in Javascript to replace all string occurrences.

replace() method

Use regex with global modifier g to replace all string occurrences

const regex = /wagga/g; // use global modifier
const input = 'wagga wagga';

const output = input.replace(regex, 'mogu');
console.log(output); // mogu mogu

Beware that if we don't specify global modifier in regex, replace() will just replace the first occurrence

const regex = /wagga/; // no global modifier
const input = 'wagga wagga';

const output = input.replace(regex, 'mogu');
console.log(output); // mogu wagga

The result is same if we use a substitution string

const substr = 'wagga';
const input = 'wagga wagga';

const output = input.replace(substr, 'mogu');
console.log(output); // mogu wagga

replaceAll() method

This method is added in ECMAScript 2021.

Unlike replace(), use string in replaceAll() will replace all occurrences

const substr = 'wagga'; // ordinary string
const input = 'wagga wagga';

const output = input.replaceAll(substr, 'mogu');
console.log(output); // mogu mogu

The syntax is nicer compare to replace() with regex global modifier.

replaceAll() also can accept regex, but the regex must have global modifer, otherwise, it'll throw an error

const regex = /wagga/g;
const input = 'wagga wagga';

const output = input5.replaceAll(regex5, 'mogu');
console.log(output); // mogu mogu

The syntax above is exactly same as replace(). If we don't do advanced stuff, using a substitution string is more recommended than regex.

Below is an example if we don't specify global modifer, it'll throw an error

const regex = /wagga/; // no global modifier
const input = 'wagga wagga';

const output = input.replaceAll(regex, 'mogu');
console.log(output); // error String.prototype.replaceAll called with a non-global RegExp argument

Playground

Try this Stackblitz