camelCase function

Converts a string to camelCase; acronyms are words (XMLHttpRequest → xmlHttpRequest).

import { camelCase } from 'utils';

Signature

export function camelCase(input: string): string

Parameters

Name	Description
input	The identifier or sentence to convert, in any case style.

Returns

The camelCase string; '' when the input has no word.

Example

camelCase('user-id'); // 'userId'
camelCase('XML HTTP request'); // 'xmlHttpRequest'

Tests

Line coverage: 100 %.

• ✅ converts "user-id" to "userId"
• ✅ converts "user_id" to "userId"
• ✅ converts "User Id" to "userId"
• ✅ converts "USER_ID" to "userId"
• ✅ converts "userId" to "userId"
• ✅ converts "XMLHttpRequest" to "xmlHttpRequest"
• ✅ converts "speed 2 knots" to "speed2Knots"
• ✅ converts "" to ""

Source

src/string/camel-case.ts (on GitHub)

Uses

• capitalize: Upper-cases the first character of a string, even outside the basic Unicode plane.
• splitWords: Splits a string into words, whatever its case style (camelCase, kebab-case, snake_case, spaces…), in one pass.

Files it needs

src/string/camel-case.ts imports, directly or not:

• src/string/capitalize.ts
• src/string/split-words.ts

Source code

import { capitalize } from './capitalize';
import { splitWords } from './split-words';

/**
 * Converts a string to camelCase; acronyms are words (`XMLHttpRequest` → `xmlHttpRequest`).
 *
 * @param input - The identifier or sentence to convert, in any case style.
 * @returns The camelCase string; `''` when the input has no word.
 * @example
 * camelCase('user-id'); // 'userId'
 * camelCase('XML HTTP request'); // 'xmlHttpRequest'
 */
export function camelCase(input: string): string {
  return splitWords(input)
    .map((word, index) => (index === 0 ? word.toLowerCase() : capitalize(word.toLowerCase())))
    .join('');
}

Test file

import { camelCase } from './camel-case';

describe(camelCase, () => {
  it.for([
    ['user-id', 'userId'],
    ['user_id', 'userId'],
    ['User Id', 'userId'],
    ['USER_ID', 'userId'],
    ['userId', 'userId'],
    ['XMLHttpRequest', 'xmlHttpRequest'],
    ['speed 2 knots', 'speed2Knots'],
    ['', ''],
  ] as const)('converts %j to %j', ([input, expected]) => {
    expect(camelCase(input)).toBe(expected);
  });
});

Keywords: camel, case, strings, function