README
inheritedPropertyDescriptor
Return a property descriptor for an object's inherited property.
Installation
npm install @stdlib/utils-inherited-property-descriptor
Usage
var inheritedPropertyDescriptor = require( '@stdlib/utils-inherited-property-descriptor' );
inheritedPropertyDescriptor( obj, property[, level] )
Returns a property descriptor for an object's inherited property.
function Foo() {
return this;
}
Foo.prototype.bar = 'foo';
var obj = new Foo();
var desc = inheritedPropertyDescriptor( obj, 'bar' );
// returns {'configurable':true,'enumerable':true,'writable':true,'value':'foo'}
By default, the function walks an object's entire prototype chain. To limit the inheritance level, provide a level
argument.
var inherit = require( '@stdlib/utils-inherit' );
function Bar() {
return this;
}
Bar.prototype.beep = 'boop';
function Foo() {
Bar.call( this );
return this;
}
inherit( Foo, Bar );
var f = new Foo();
var desc = inheritedPropertyDescriptor( f, 'beep', 1 );
// returns null
Notes
This function differs from the built-in
Object.getOwnPropertyDescriptor()
as follows:- If provided
null
orundefined
, the function returnsnull
, rather than throwing an error. - If an object does not have a provided inherited property, the function returns
null
, rather thanundefined
.
- If provided
Examples
var defineProperty = require( '@stdlib/utils-define-property' );
var inheritedPropertyDescriptor = require( '@stdlib/utils-inherited-property-descriptor' );
function Foo() {
this.beep = 'boop';
this.a = {
'b': 'c'
};
defineProperty( this, 'baz', {
'value': 'qux',
'configurable': true,
'writable': true,
'enumerable': false
});
return this;
}
Foo.prototype.foo = [ 'bar' ];
var obj = new Foo();
var desc = inheritedPropertyDescriptor( obj, 'foo' );
console.log( desc );
// => {'configurable':true,'enumerable':true,'writable':true,'value':['bar']}
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.
Community
License
See LICENSE.
Copyright
Copyright © 2016-2022. The Stdlib Authors.