146 lines
2.8 KiB
Markdown
146 lines
2.8 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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# instanceOf
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> Test whether a value has in its prototype chain a specified constructor as a prototype property.
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<section class="intro">
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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 instanceOf = require( '@stdlib/assert/instance-of' );
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```
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#### instanceOf( value, constructor )
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Tests whether a `value` has in its prototype chain a specified `constructor` as a `prototype` property.
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```javascript
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var inherit = require( '@stdlib/utils/inherit' );
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function Foo() {
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return this;
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}
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function Bar() {
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return this;
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}
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inherit( Bar, Foo );
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var bar = new Bar();
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var bool = instanceOf( bar, Foo );
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// returns true
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```
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</section>
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<!-- /.usage -->
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<section class="notes">
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## Notes
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- The function throws a `TypeError` if provided a `constructor` argument which is not callable.
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```javascript
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var bool = instanceOf( {}, null );
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// throws <TypeError>
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```
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- While the prototype of an `object` created using object literal notion is `undefined`, the function returns `true` when provided an `object` literal and the `Object` constructor. This maintains consistent behavior with the `instanceof` operator.
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```javascript
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var bool = ( {} instanceof Object );
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// returns true
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bool = instanceOf( {}, Object );
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// returns true
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```
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</section>
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<!-- /.notes -->
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<section class="examples">
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## Examples
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<!-- eslint no-undef: "error" -->
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```javascript
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var Number = require( '@stdlib/number/ctor' );
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var instanceOf = require( '@stdlib/assert/instance-of' );
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var bool = instanceOf( [], Array );
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// returns true
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bool = instanceOf( [], Object );
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// returns true
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bool = instanceOf( {}, Object );
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// returns true
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bool = instanceOf( new Date(), Date );
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// returns true
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bool = instanceOf( /.*/, RegExp );
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// returns true
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bool = instanceOf( instanceOf, Function );
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// returns true
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bool = instanceOf( null, Object );
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// returns false
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bool = instanceOf( 5, Number );
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// returns false
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bool = instanceOf( '5', String );
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// returns false
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bool = instanceOf( void 0, Object );
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// returns false
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bool = instanceOf( {}, Array );
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// returns false
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bool = instanceOf( {}, Function );
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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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</section>
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<!-- /.links -->
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