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Nov 9, 2023
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inherited-nonenumerable-property-names

README.md

inheritedNonEnumerablePropertyNames

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

Usage

var inheritedNonEnumerablePropertyNames = require( '@stdlib/utils/inherited-nonenumerable-property-names' );

inheritedNonEnumerablePropertyNames( obj[, level] )

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

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 keys = inheritedNonEnumerablePropertyNames( 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 keys = inheritedNonEnumerablePropertyNames( f, 1 );
// e.g., returns [ 'beep', ... ]

Notes

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

Examples

var defineProperty = require( '@stdlib/utils/define-property' );
var inheritedNonEnumerablePropertyNames = require( '@stdlib/utils/inherited-nonenumerable-property-names' );

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

Foo.prototype.foo = [ 'bar' ];
defineProperty( Foo.prototype, 'bip', {
    'configurable': false,
    'enumerable': false,
    'writable': false,
    'value': 'bop'
});

var obj = new Foo();
var keys = inheritedNonEnumerablePropertyNames( obj );

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

See Also