118 lines
2.4 KiB
Markdown
118 lines
2.4 KiB
Markdown
<!--
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@license Apache-2.0
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Copyright (c) 2018 The Stdlib Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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-->
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# isNativeFunction
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> Test if a value is a native function.
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<section class="intro">
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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].
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</section>
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<!-- /.intro -->
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<section class="usage">
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## Usage
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```javascript
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var isNativeFunction = require( '@stdlib/assert/is-native-function' );
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```
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#### isNativeFunction( value )
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Tests if a `value` is a native `function`.
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```javascript
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var bool = isNativeFunction( Date );
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// returns true
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function beep() {
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console.log( 'beep' );
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}
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bool = isNativeFunction( beep );
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// returns false
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```
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</section>
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<!-- /.usage -->
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<section class="examples">
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## Examples
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<!-- eslint-disable no-empty-function, no-restricted-syntax, stdlib/no-builtin-math -->
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<!-- eslint no-undef: "error" -->
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```javascript
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var isNativeFunction = require( '@stdlib/assert/is-native-function' );
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var bool = isNativeFunction( Math.sqrt );
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// returns true
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bool = isNativeFunction( Date );
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// returns true
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bool = isNativeFunction( RegExp );
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// returns true
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bool = isNativeFunction( function foo() {} );
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// returns false
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bool = isNativeFunction( 'beep' );
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// returns false
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bool = isNativeFunction( 5 );
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// returns false
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bool = isNativeFunction( true );
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// returns false
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bool = isNativeFunction( null );
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// returns false
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bool = isNativeFunction( [] );
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// returns false
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bool = isNativeFunction( {} );
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// returns false
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```
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</section>
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<!-- /.examples -->
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<section class="links">
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[mdn-builtins]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects
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[node-js-add-ons]: https://nodejs.org/api/addons.html
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[webassembly]: https://webassembly.org/
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</section>
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<!-- /.links -->
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