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    @stdlib/assert-instance-of
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    0.0.8 • Public • Published

    instanceOf

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    Test whether a value has in its prototype chain a specified constructor as a prototype property.

    Installation

    npm install @stdlib/assert-instance-of

    Usage

    var instanceOf = require( '@stdlib/assert-instance-of' );

    instanceOf( value, constructor )

    Tests whether a value has in its prototype chain a specified constructor as a prototype property.

    var inherit = require( '@stdlib/utils-inherit' );
    
    function Foo() {
        return this;
    }
    
    function Bar() {
        return this;
    }
    inherit( Bar, Foo );
    
    var bar = new Bar();
    
    var bool = instanceOf( bar, Foo );
    // returns true

    Notes

    • The function throws a TypeError if provided a constructor argument which is not callable.

      var bool = instanceOf( {}, null );
      // throws <TypeError>
    • 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.

      var bool = ( {} instanceof Object );
      // returns true
      
      bool = instanceOf( {}, Object );
      // returns true

    Examples

    var Number = require( '@stdlib/number-ctor' );
    var instanceOf = require( '@stdlib/assert-instance-of' );
    
    var bool = instanceOf( [], Array );
    // returns true
    
    bool = instanceOf( [], Object );
    // returns true
    
    bool = instanceOf( {}, Object );
    // returns true
    
    bool = instanceOf( new Date(), Date );
    // returns true
    
    bool = instanceOf( /.*/, RegExp );
    // returns true
    
    bool = instanceOf( instanceOf, Function );
    // returns true
    
    bool = instanceOf( null, Object );
    // returns false
    
    bool = instanceOf( 5, Number );
    // returns false
    
    bool = instanceOf( '5', String );
    // returns false
    
    bool = instanceOf( void 0, Object );
    // returns false
    
    bool = instanceOf( {}, Array );
    // returns false
    
    bool = instanceOf( {}, Function );
    // returns false

    See Also


    Notice

    This package is part of 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, see the main project repository.

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    License

    See LICENSE.

    Copyright

    Copyright © 2016-2022. The Stdlib Authors.

    Install

    npm i @stdlib/assert-instance-of

    Homepage

    stdlib.io

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    8,646

    Version

    0.0.8

    License

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    39.6 kB

    Total Files

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    Collaborators

    • stdlib-bot
    • kgryte
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    • rreusser