For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt, and this page is available as Markdown at /reference/string/startCase.md.
Install massaman

    startCase es-toolkit

    Converts the first letter of each word in a string to uppercase.

    const converted = startCase(str);

    Usage

    startCase(str)

    Use startCase when you want to convert a string to start case (where the first letter of each word is capitalized). It capitalizes the first letter of each word, converts the rest to lowercase, and joins the words with spaces.

    import { startCase } from 'es-toolkit/string';

// Basic usage
startCase('hello world'); // 'Hello World'
startCase('HELLO WORLD'); // 'Hello World'

// Converting camelCase or PascalCase
startCase('fooBar'); // 'Foo Bar'
startCase('PascalCase'); // 'Pascal Case'

// Words connected with hyphens or underscores
startCase('hello-world'); // 'Hello World'
startCase('hello_world'); // 'Hello World'

    It also correctly handles strings with various delimiters and special characters.

    import { startCase } from 'es-toolkit/string';

// Cases with multiple delimiters
startCase('--foo-bar--'); // 'Foo Bar'
startCase('__FOO_BAR__'); // 'Foo Bar'

// Handling consecutive uppercase letters and numbers
startCase('XMLHttpRequest'); // 'Xml Http Request'
startCase('_abc_123_def'); // 'Abc 123 Def'

// Cases with empty strings or only meaningless delimiters
startCase('_-_-_-_'); // ''
startCase('12abc 12ABC'); // '12 Abc 12 Abc'

    Parameters

    strstringrequired

    The string to convert to start case.

    Returns

    Returns a new string with the first letter of each word capitalized and joined with spaces.

    string

    Try It

    ::: sandpack

    import { startCase } from 'es-toolkit/string';

console.log(startCase('startCase'));

    :::

    Source: es-toolkit

    Re-exported verbatim from es-toolkit. Implementation, edge cases, and performance behavior are owned upstream. This page mirrors the documentation at the pinned version; the linked source is authoritative.