titleCase function

Converts a string to Title Case: words separated by spaces, each capitalized, acronyms kept.

import { titleCase } from 'utils';

Signature

export function titleCase(input: string): string

Parameters

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

Returns

The title; '' when the input has no word.

Example

titleCase('engine-room'); // 'Engine Room'
titleCase('maxSpeedGPS'); // 'Max Speed GPS'

Tests

Line coverage: 100 %.

• ✅ converts "engine-room" to "Engine Room"
• ✅ converts "maxSpeedGPS" to "Max Speed GPS"
• ✅ converts "user_id" to "User Id"
• ✅ converts "HTTP status code" to "HTTP Status Code"
• ✅ converts "speed2" to "Speed 2"
• ✅ converts "" to ""

Source

src/string/title-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/title-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 Title Case: words separated by spaces, each capitalized, acronyms kept.
 *
 * @param input - The identifier or sentence to convert, in any case style.
 * @returns The title; `''` when the input has no word.
 * @example
 * titleCase('engine-room'); // 'Engine Room'
 * titleCase('maxSpeedGPS'); // 'Max Speed GPS'
 */
export function titleCase(input: string): string {
  return splitWords(input)
    .map((word) => (word === word.toUpperCase() ? word : capitalize(word.toLowerCase())))
    .join(' ');
}

Test file

import { titleCase } from './title-case';

describe(titleCase, () => {
  it.for([
    ['engine-room', 'Engine Room'],
    ['maxSpeedGPS', 'Max Speed GPS'],
    ['user_id', 'User Id'],
    ['HTTP status code', 'HTTP Status Code'],
    ['speed2', 'Speed 2'],
    ['', ''],
  ] as const)('converts %j to %j', ([input, expected]) => {
    expect(titleCase(input)).toBe(expected);
  });
});

Keywords: title, case, strings, function