Test whether a value has in its prototype chain a specified constructor as a prototype property.
APACHE-2.0 License
Test whether a value has in its prototype chain a specified constructor as a prototype property.
npm install @stdlib/assert-instance-of
Alternatively,
script
tag without installation and bundlers, use the ES Module available on the esm
branch (see README).deno
branch (see README for usage intructions).umd
branch (see README).The branches.md file summarizes the available branches and displays a diagram illustrating their relationships.
To view installation and usage instructions specific to each branch build, be sure to explicitly navigate to the respective README files on each branch, as linked to above.
var instanceOf = require( '@stdlib/assert-instance-of' );
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
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 Object = require( '@stdlib/object-ctor' );
var bool = ( {} instanceof Object );
// returns true
bool = instanceOf( {}, Object );
// returns true
var Number = require( '@stdlib/number-ctor' );
var Object = require( '@stdlib/object-ctor' );
var Function = require( '@stdlib/function-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
@stdlib/assert-is-prototype-of
: test if an object's prototype chain contains a provided prototype.
@stdlib/utils-constructor-name
: determine the name of a value's constructor.
@stdlib/utils-inherit
: implement prototypical inheritance by replacing the prototype of one constructor with the prototype of another constructor.
@stdlib/utils-type-of
: determine a value's type.
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.
See LICENSE.
Copyright © 2016-2024. The Stdlib Authors.