README.md

inheritedWritablePropertySymbols

Return an array of an object's inherited writable symbol properties.

Usage

var inheritedWritablePropertySymbols = require( '@stdlib/utils/inherited-writable-property-symbols' );

inheritedWritablePropertySymbols( obj[, level] )

Returns an array of an object's inherited writable symbol properties.

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

var hasSymbols = hasSymbolSupport();
var symbols;
var f;

function Foo() {
    if ( hasSymbols ) {
        defineProperty( this, Symbol( 'a' ), {
            'configurable': false,
            'enumerable': false,
            'writable': true,
            'value': 'a'
        });
    }
    return this;
}

if ( hasSymbols ) {
    defineProperty( Foo.prototype, Symbol( 'b' ), {
        'configurable': false,
        'enumerable': false,
        'writable': true,
        'value': 'b'
    });
}

f = new Foo();
symbols = inheritedWritablePropertySymbols( f );

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

var symbols = inheritedWritablePropertySymbols( [], 1 );

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 defineProperty = require( '@stdlib/utils/define-property' );
var hasSymbolSupport = require( '@stdlib/assert/has-symbol-support' );
var Symbol = require( '@stdlib/symbol/ctor' );
var inheritedWritablePropertySymbols = require( '@stdlib/utils/inherited-writable-property-symbols' );

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

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

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

obj = new Foo();
symbols = inheritedWritablePropertySymbols( obj );

console.log( symbols );

---

See Also

• @stdlib/utils/inherited-writable-property-names: return an array of an object's inherited writable property names.
• @stdlib/utils/writable-property-symbols: return an array of an object's own writable symbol properties.
• @stdlib/utils/writable-property-symbols-in: return an array of an object's own and inherited writable symbol properties.
• @stdlib/utils/properties: return an array of an object's own enumerable and non-enumerable property names and symbols.