npm package: @stdlib/regexp-function-name
Description: Return a regular expression to capture a function name.
Author: The Stdlib Authors
Latest version: 0.2.3

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<details>
  <summary>
    About stdlib...
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  <p>We believe in a future in which the web is a preferred environment for numerical computation. To help realize this future, we've built stdlib. stdlib is a standard library, with an emphasis on numerical and scientific computation, written in JavaScript (and C) for execution in browsers and in Node.js.</p>
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# reFunctionName

[![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 capture a function name.

<section class="installation">

## Installation

```bash
npm install @stdlib/regexp-function-name
```

</section>

<section class="usage">

## Usage

```javascript
var reFunctionName = require( '@stdlib/regexp-function-name' );
```

#### reFunctionName()

Returns a [regular expression][regexp] to capture a `function` name.

```javascript
function beep() {
    return 'boop';
}

var RE_FUNCTION_NAME = reFunctionName();
var str = RE_FUNCTION_NAME.exec( beep.toString() )[ 1 ];
// returns 'beep'
```

#### reFunctionName.REGEXP

[Regular expression][regexp] to capture a `function` name.

<!-- eslint-disable stdlib/no-builtin-math -->

```javascript
var str = reFunctionName.REGEXP.exec( Math.sqrt.toString() )[ 1 ];
// returns 'sqrt'
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

<!-- eslint-disable func-names, no-restricted-syntax, no-empty-function, stdlib/no-builtin-math -->

<!-- eslint no-undef: "error" -->

```javascript
var Int8Array = require( '@stdlib/array-int8' );
var reFunctionName = require( '@stdlib/regexp-function-name' );
var RE_FUNCTION_NAME = reFunctionName();

function fname( fcn ) {
    return RE_FUNCTION_NAME.exec( fcn.toString() )[ 1 ];
}

var f = fname( Math.sqrt );
// returns 'sqrt'

f = fname( Int8Array );
// returns 'Int8Array'

f = fname( Object.prototype.toString );
// returns 'toString'

f = fname( function () {} );
// returns ''
```

</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/utils-function-name`][@stdlib/utils/function-name]</span><span class="delimiter">: </span><span class="description">determine a function's name.</span>

</section>

<!-- /.related -->

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<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-function-name.svg
[npm-url]: https://npmjs.org/package/@stdlib/regexp-function-name

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

[coverage-image]: https://img.shields.io/codecov/c/github/stdlib-js/regexp-function-name/main.svg
[coverage-url]: https://codecov.io/github/stdlib-js/regexp-function-name?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-function-name/tree/deno
[deno-readme]: https://github.com/stdlib-js/regexp-function-name/blob/deno/README.md
[umd-url]: https://github.com/stdlib-js/regexp-function-name/tree/umd
[umd-readme]: https://github.com/stdlib-js/regexp-function-name/blob/umd/README.md
[esm-url]: https://github.com/stdlib-js/regexp-function-name/tree/esm
[esm-readme]: https://github.com/stdlib-js/regexp-function-name/blob/esm/README.md
[branches-url]: https://github.com/stdlib-js/regexp-function-name/blob/main/branches.md

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

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

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

[@stdlib/utils/function-name]: https://www.npmjs.com/package/@stdlib/utils-function-name

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

</section>

<!-- /.links -->