capitalizeEachWord

1/**
2 * Capitalizes the first letter of each word in a string.
3 *
4 * @param str - The input string.
5 * @returns A new string with each word's first character capitalized.
6 */
7export function capitalizeEachWord(str: string): string {
8  return str.replace(/\b\w/g, char => char.toUpperCase());
9}

• Regex-Based Efficiency

  Uses a compact and efficient regular expression (\b\w) to target word boundaries, ensuring broad language support and fast execution.

• Simple and Readable Implementation

  Easy to understand and integrate into larger formatting pipelines.

• Non-destructive Transformation

  Only the first letter of each word is altered, preserving the rest of the word’s original casing (can be layered with .toLowerCase() if stricter formatting is needed).

Tests | Examples

1test('capitalizeEachWord - basic sentence', () => {
2  expect(capitalizeEachWord('hello world')).toBe('Hello World');
3});
4
5test('capitalizeEachWord - multiple spaces', () => {
6  expect(capitalizeEachWord('  multiple   spaces  here'))
7    .toBe('  Multiple   Spaces  Here');
8});
9
10test('capitalizeEachWord - mixed case', () => {
11  expect(capitalizeEachWord('javaScript IS awesome'))
12    .toBe('JavaScript IS Awesome');
13});
14
15test('capitalizeEachWord - numbers and symbols', () => {
16  expect(capitalizeEachWord('123 go! this is @test'))
17    .toBe('123 Go! This Is @Test');
18});
19
20test('capitalizeEachWord - empty string', () => {
21  expect(capitalizeEachWord('')).toBe('');
22});
23
24test('capitalizeEachWord - single word', () => {
25  expect(capitalizeEachWord('example')).toBe('Example');
26});

Common Use Cases

• Formatting Titles or Headlines

  Convert strings like "the quick brown fox" → "The Quick Brown Fox" for display in blogs, news apps, or product names.

• Improving Readability of Raw Input

  Reformat database or API responses to be more human-readable — e.g., "john doe" → "John Doe".

• Auto-formatting Form Inputs

  Automatically capitalize names or addresses in real-time as users type (e.g., billing forms or contact pages).

• Generating UI Labels

  Useful when creating labels dynamically from field names or keys like "user_name" → "User_Name" → "User Name" → "User Name".

• Custom Report Generation

  Helpful in dashboards, analytics, or PDF exports where display formatting matters.