# isNativeFunction
> Test if a value is a native function.
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].
## 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
```
## Examples
```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
```
[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/