String

`String.prototype.replaceAll`

Returns a new string with all matches of a pattern replaced by a replacement

Syntax

JavaScript

string.replaceAll(pattern, replacement)

Parameters

Parameter	Type	Description
pattern	string \| RegExp	Pattern to search for (RegExp must have global flag)
replacement	string \| Function	Replacement string or function

Return Value

A new string with all replacements made

Examples

Basic Usage

const str = 'aabbcc';
console.log(str.replaceAll('b', 'x')); // 'aaxxcc'

Practical Example

const template = 'Hello {name}, welcome to {place}!';
const result = template
  .replaceAll('{name}', 'Alice')
  .replaceAll('{place}', 'Wonderland');
console.log(result); // 'Hello Alice, welcome to Wonderland!'

Advanced Usage

const csv = '1,2,3,4,5';
console.log(csv.replaceAll(',', ' | ')); // '1 | 2 | 3 | 4 | 5'

Understanding String.prototype.replaceAll

The String.prototype.replaceAll method in JavaScript returns a new string with all matches of a pattern replaced by a replacement. It belongs to the String object and is one of the most widely used methods for working with string values in modern JavaScript and TypeScript applications.

The method signature is string.replaceAll(pattern, replacement). It accepts 2 parameters: pattern, replacement. When called, it returns a new string with all replacements made. Understanding when and how to use replaceAll() helps you write more expressive, readable code.

Common use cases for String.prototype.replaceAll include data transformation, input validation, API response processing, and building reusable utility functions. It works well alongside related methods like string-replace, string-match, string-split, enabling you to chain operations together for complex data manipulation pipelines.

Browser support for String.prototype.replaceAll is excellent across all modern browsers including Chrome, Firefox, Safari, and Edge. It is also fully supported in Node.js and Deno. For older environments, transpilation with Babel or a polyfill may be needed.