How to Replace All Occurrences of a String in JavaScript?

Last Updated : 19 Nov, 2024

Here are different approaches to replace all occurrences of a string in JavaScript.

1. Using string.replace() Method

The string.replace() method is used to replace a part of the given string with another string or a regular expression. The original string will remain unchanged.

Syntax

str.replace(replacing_string, Original_string);

JavaScript

// Origin String
const str = 'Welcome GeeksforGeeks, Welcome geeks';

// Replace all occurrence of Welcome with Hello
const newString = str.replace(/Welcome/gi, 'Hello');

// Display the result
console.log(newString);

Output

Hello GeeksforGeeks, Hello geeks

2. Using String split() and join() Methods

We can split the strings of text with the split() method and join strings using the replace characters with the join() method.

JavaScript

// Original String
const str = 'Welcome GeeksforGeeks, Welcome geeks';

// Replace all occurrence of Welcome with Hello
const newString = str.split('Welcome').join('Hello');

// Display the result
console.log(newString);

Output

Hello GeeksforGeeks, Hello geeks

3. Using replaceAll() Method

The replaceAll() method is used to replace all the matches of a string with a specified string or a regular expression. The original string is left unchanged after this operation.

JavaScript

// Original String
const str = 'Welcome GeeksforGeeks, Welcome geeks';

// Replace all occurrences of Welcome with Hello
const newString = str.replaceAll("Welcome", "Hello");

// Display the result
console.log(newString);

Output

Hello GeeksforGeeks, Hello geeks

4. Using Regular Expression

To replace all occurrences of a string in JavaScript using a regular expression, we can use the regular expression with the global (g) Flag.

JavaScript

const str = 'Welcome GeeksforGeeks, Welcome geeks';
const searchString ="Welcome";
const replacementString ="Hello";

let regex = new RegExp(searchString, 'g');
let replacedString = str.replace(regex, replacementString);
console.log(replacedString);

Output

Hello GeeksforGeeks, Hello geeks

5. Using reduce() Method

We can split the string into an array of substrings using the split() method, and then we use the reduce() method to concatenate the substrings, inserting the replacement string where the original substring occurs. This method gives us fine control over the replacement process and can be useful for more complex string manipulations.