String

`String.prototype.normalize`

Returns the Unicode Normalization Form of the string

Syntax

JavaScript

string.normalize(form?)

Parameters

Parameter	Type	Description
form	'NFC' \| 'NFD' \| 'NFKC' \| 'NFKD'	Unicode normalization form. Defaults to NFC

Return Value

A string containing the normalized form

Examples

Basic Usage

const str1 = '\u00F1'; // ñ
const str2 = '\u006E\u0303'; // ñ (n + combining tilde)
console.log(str1 === str2); // false
console.log(str1.normalize() === str2.normalize()); // true

Practical Example

const accented = 'caf\u00E9';
const decomposed = accented.normalize('NFD');
console.log(decomposed.length); // 5

Advanced Usage

const str = '\uFB01'; // ﬁ ligature
console.log(str.normalize('NFKD')); // 'fi'

Understanding String.prototype.normalize

The String.prototype.normalize method in JavaScript returns the Unicode Normalization Form of the string. 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.normalize(form?). It accepts 1 parameter: form. When called, it returns a string containing the normalized form. Understanding when and how to use normalize() helps you write more expressive, readable code.

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

Browser support for String.prototype.normalize 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.