inheritedNonEnumerableProperties

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

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', ... ]