npm package: @stdlib/assert-is-native-function
Description: Test if a value is a native function.
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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</details>

# isNativeFunction

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

> Test if a value is a native function.

<section class="intro">

Native functions execute native code that is typically not written in JavaScript, but a lower-level language like C++. This includes the JavaScript [built-in functions][mdn-builtins], functions implemented using [Node.js C/C++ addons][node-js-add-ons], and code compiled via [WebAssembly][webassembly].

</section>

<!-- /.intro -->

<section class="installation">

## Installation

```bash
npm install @stdlib/assert-is-native-function
```

</section>

<section class="usage">

## Usage

```javascript
var isNativeFunction = require( '@stdlib/assert-is-native-function' );
```

#### isNativeFunction( value )

Tests if a `value` is a native `function`.

```javascript
var bool = isNativeFunction( Date );
// returns true

function beep() {
    console.log( 'beep' );
}

bool = isNativeFunction( beep );
// returns false
```

</section>

<!-- /.usage -->

<section class="examples">

## Examples

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

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

```javascript
var isNativeFunction = require( '@stdlib/assert-is-native-function' );

var bool = isNativeFunction( Math.sqrt );
// returns true

bool = isNativeFunction( Date );
// returns true

bool = isNativeFunction( RegExp );
// returns true

bool = isNativeFunction( function foo() {} );
// returns false

bool = isNativeFunction( 'beep' );
// returns false

bool = isNativeFunction( 5 );
// returns false

bool = isNativeFunction( true );
// returns false

bool = isNativeFunction( null );
// returns false

bool = isNativeFunction( [] );
// returns false

bool = isNativeFunction( {} );
// returns false
```

</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-function`][@stdlib/assert/is-function]</span><span class="delimiter">: </span><span class="description">test if a value is a function.</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/assert-is-native-function.svg
[npm-url]: https://npmjs.org/package/@stdlib/assert-is-native-function

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

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

[stdlib-license]: https://raw.githubusercontent.com/stdlib-js/assert-is-native-function/main/LICENSE

[mdn-builtins]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects

[node-js-add-ons]: https://nodejs.org/api/addons.html

[webassembly]: https://webassembly.org/

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

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

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

</section>

<!-- /.links -->