npm package: @stdlib/regexp-whitespace
Description: Return a regular expression to match a white space character.
Author: The Stdlib Authors
Latest version: 0.2.3

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# reWhitespace

[![NPM version][npm-image]][npm-url] [![Build Status][test-image]][test-url] [![Coverage Status][coverage-image]][coverage-url] <!-- [![dependencies][dependencies-image]][dependencies-url] -->

> [Regular expression][regexp] to match a [white space][whitespace] character.

<section class="installation">

## Installation

```bash
npm install @stdlib/regexp-whitespace
```

</section>

<section class="usage">

## Usage

```javascript
var reWhitespace = require( '@stdlib/regexp-whitespace' );
```

#### reWhitespace( \[options] )

Returns a [regular expression][regexp] to match a [white space][whitespace] character.

```javascript
var RE_WHITESPACE = reWhitespace();

var bool = RE_WHITESPACE.test( '\n' );
// returns true

bool = RE_WHITESPACE.test( ' ' );
// returns true
```

The function accepts an `options` object with optional properties:

-   **flags**: `string` specifying regular expression [flags][mdn-regexp-flags]. Default: `''`.
-   **capture**: `boolean` indicating whether to create a capture group for the match. Default: `false`.

By default, the function returns a regular expression which does not have any flags specified. To specify [flags][mdn-regexp-flags], set the `flags` option with a list of flags (which may be in any order).

```javascript
var RE_WHITESPACE = reWhitespace({
    'flags': 'gm'
});

var str = 'Hello World!';
var bool = RE_WHITESPACE.test( str );
// returns true

bool = RE_WHITESPACE.test( str );
// returns false
```

By default, the function returns a regular expression which does not capture the part of a string matching the regular expression. To capture matches, set the `capture` option.

```javascript
var RE_WHITESPACE = reWhitespace({
    'capture': true
});
var str = 'Hello World!';
var arr = str.split( RE_WHITESPACE );
// returns [ 'Hello', ' ', 'World!' ]
```

#### reWhitespace.REGEXP

[Regular expression][regexp] to match a [white space][whitespace] character.

```javascript
var bool = reWhitespace.REGEXP.test( '\n' );
// returns true

bool = reWhitespace.REGEXP.test( '\\n' );
// returns false
```

#### reWhitespace.REGEXP_CAPTURE

[Regular expression][regexp] to capture characters matching a [white space][whitespace] character.

```javascript
var replace = require( '@stdlib/string-replace' );

var str = 'Duplicate capture';
var out = replace( str, reWhitespace.REGEXP_CAPTURE, '$1$1' );
// returns 'Duplicate  capture'
```

</section>

<!-- /.usage -->

<section class="notes">

## Notes

-   Matches the `25` characters defined as white space ("WSpace=Y","WS") characters in the Unicode `9.0` character database.

-   Matches one related white space character without the Unicode character property "WSpace=Y" (zero width non-breaking space which was deprecated as of Unicode 3.2).

-   The `REGEXP` regular expression is defined as

    ```text
    /[\u0009\u000A\u000B\u000C\u000D\u0020\u0085\u00A0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u2028\u2029\u202F\u205F\u3000\uFEFF]/
    ```

-   The `REGEXP_CAPTURE` regular expression is defined as

    ```text
    /([\u0009\u000A\u000B\u000C\u000D\u0020\u0085\u00A0\u1680\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200A\u2028\u2029\u202F\u205F\u3000\uFEFF])/
    ```

</section>

<!-- /.notes -->

<section class="examples">

## Examples

<!-- eslint no-undef: "error",  stdlib/doctest: "off" -->

```javascript
var reWhitespace = require( '@stdlib/regexp-whitespace' );

var RE_WHITESPACE = reWhitespace();

var bool = RE_WHITESPACE.test( 'beep boop' );
// returns true

bool = RE_WHITESPACE.test( '\n' );
// returns true

bool = RE_WHITESPACE.test( '\r' );
// returns true

bool = RE_WHITESPACE.test( '\t' );
// returns true

bool = RE_WHITESPACE.test( 'beep' );
// returns false

var str = 'This is\na newline\r\ndelimited string.';

var arr = str.split( RE_WHITESPACE );
// returns [ 'This', 'is', 'a', 'newline', '', 'delimited', 'string.' ]
```

</section>

<!-- /.examples -->

<!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->

<section class="related">

* * *

## See Also

-   <span class="package-name">[`@stdlib/assert-is-whitespace`][@stdlib/assert/is-whitespace]</span><span class="delimiter">: </span><span class="description">test whether a string contains only white space characters.</span>

</section>

<!-- /.related -->

<!-- Section for all links. Make sure to keep an empty line after the `section` element and another before the `/section` close. -->


<section class="main-repo" >

* * *

## Notice

This package is part of [stdlib][stdlib], a standard library for JavaScript and Node.js, with an emphasis on numerical and scientific computing. The library provides a collection of robust, high performance libraries for mathematics, statistics, streams, utilities, and more.

For more information on the project, filing bug reports and feature requests, and guidance on how to develop [stdlib][stdlib], see the main project [repository][stdlib].

#### Community

[![Chat][chat-image]][chat-url]

---

## License

See [LICENSE][stdlib-license].


## Copyright

Copyright &copy; 2016-2026. The Stdlib [Authors][stdlib-authors].

</section>

<!-- /.stdlib -->

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<section class="links">

[npm-image]: http://img.shields.io/npm/v/@stdlib/regexp-whitespace.svg
[npm-url]: https://npmjs.org/package/@stdlib/regexp-whitespace

[test-image]: https://github.com/stdlib-js/regexp-whitespace/actions/workflows/test.yml/badge.svg?branch=v0.2.3
[test-url]: https://github.com/stdlib-js/regexp-whitespace/actions/workflows/test.yml?query=branch:v0.2.3

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/regexp-whitespace/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/regexp-whitespace?branch=main

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[stdlib]: https://github.com/stdlib-js/stdlib

[stdlib-authors]: https://github.com/stdlib-js/stdlib/graphs/contributors

[umd]: https://github.com/umdjs/umd
[es-module]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Modules

[deno-url]: https://github.com/stdlib-js/regexp-whitespace/tree/deno
[deno-readme]: https://github.com/stdlib-js/regexp-whitespace/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/regexp-whitespace/tree/umd
[umd-readme]: https://github.com/stdlib-js/regexp-whitespace/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/regexp-whitespace/tree/esm
[esm-readme]: https://github.com/stdlib-js/regexp-whitespace/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/regexp-whitespace/blob/main/branches.md

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/regexp-whitespace/main/LICENSE

[regexp]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions

[whitespace]: https://en.wikipedia.org/wiki/Whitespace_character

[mdn-regexp-flags]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions#advanced_searching_with_flags_2

<!-- <related-links> -->

[@stdlib/assert/is-whitespace]: https://www.npmjs.com/package/@stdlib/assert-is-whitespace

<!-- </related-links> -->

</section>

<!-- /.links -->