inheritedNonEnumerableProperties

Return an array of an object's inherited non-enumerable property names and symbols.

Installation

npm install @stdlib/utils-inherited-nonenumerable-properties

Usage

var inheritedNonEnumerableProperties = require( '@stdlib/utils-inherited-nonenumerable-properties' );

inheritedNonEnumerableProperties( obj[, level] )

Returns an array of an object's inherited non-enumerable property names and symbols.

var defineProperty = require( '@stdlib/utils-define-property' );

function Foo() {
    this.a = 'b';
    return this;
}

defineProperty( Foo.prototype, 'beep', {
    'configurable': false,
    'enumerable': false,
    'writable': false,
    'value': 'boop'
});

var f = new Foo();
var props = inheritedNonEnumerableProperties( f );
// e.g., returns [ 'beep', ... ]

By default, the function walks an object's entire prototype chain. To limit the inheritance level, provide a level argument.

var defineProperty = require( '@stdlib/utils-define-property' );
var inherit = require( '@stdlib/utils-inherit' );

function Bar() {
    return this;
}

defineProperty( Bar.prototype, 'boop', {
    'configurable': false,
    'enumerable': false,
    'writable': false,
    'value': 'beep'
});

function Foo() {
    Bar.call( this );
    this.a = 'b';
    return this;
}

inherit( Foo, Bar );

defineProperty( Foo.prototype, 'beep', {
    'configurable': false,
    'enumerable': false,
    'writable': false,
    'value': 'boop'
});

var f = new Foo();
var pros = inheritedNonEnumerableProperties( f, 1 );
// e.g., returns [ 'beep', ... ]

Notes

Property order is not guaranteed, as object property enumeration is not specified according to the ECMAScript specification. In practice, however, most engines use insertion order to sort an object's properties, thus allowing for deterministic extraction.

Examples

var hasSymbolSupport = require( '@stdlib/assert-has-symbol-support' );
var Symbol = require( '@stdlib/symbol-ctor' );
var defineProperty = require( '@stdlib/utils-define-property' );
var inheritedNonEnumerableProperties = require( '@stdlib/utils-inherited-nonenumerable-properties' );

var hasSymbols = hasSymbolSupport();
var props;
var obj;

function Foo() {
    this.beep = 'boop';
    this.a = {
        'b': 'c'
    };
    defineProperty( this, 'baz', {
        'configurable': false,
        'enumerable': false,
        'writable': true,
        'value': 'qux'
    });
    if ( hasSymbols ) {
        this[ Symbol( 'a' ) ] = 'b';
        defineProperty( this, 'beep', {
            'configurable': false,
            'enumerable': false,
            'writable': false,
            'value': 'boop'
        });
    }
    return this;
}

Foo.prototype.c = 'd';
defineProperty( Foo.prototype, 'bip', {
    'configurable': false,
    'enumerable': false,
    'writable': false,
    'value': 'bop'
});
if ( hasSymbols ) {
    Foo.prototype[ Symbol( 'c' ) ] = 'd';
    defineProperty( Foo.prototype, Symbol( 'e' ), {
        'configurable': false,
        'enumerable': false,
        'writable': false,
        'value': 'f'
    });
}

obj = new Foo();
props = inheritedNonEnumerableProperties( obj );

console.log( props );
// e.g., => [ 'bip', ... ]

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.

License

See LICENSE.

@stdlib/utils-inherited-nonenumerable-properties

Package Exports

Readme