inheritedNonEnumerablePropertySymbols

    Return an array of an object's inherited non-enumerable symbol properties.

    Usage

    var inheritedNonEnumerablePropertySymbols = require( '@stdlib/utils/inherited-nonenumerable-property-symbols' );
    

    inheritedNonEnumerablePropertySymbols( obj[, level] )

    Returns an array of an object's inherited non-enumerable 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': false,
                'value': 'a'
            });
        }
        return this;
    }
    
    if ( hasSymbols ) {
        defineProperty( Foo.prototype, Symbol( 'b' ), {
            'configurable': false,
            'enumerable': false,
            'writable': false,
            'value': 'b'
        });
    }
    
    f = new Foo();
    symbols = inheritedNonEnumerablePropertySymbols( f );
    

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

    var symbols = inheritedNonEnumerablePropertySymbols( [], 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 inheritedNonEnumerablePropertySymbols = require( '@stdlib/utils/inherited-nonenumerable-property-symbols' );
    
    var hasSymbols = hasSymbolSupport();
    var symbols;
    var obj;
    
    function Foo() {
        this.a = 'a';
        defineProperty( this, 'b', {
            'configurable': false,
            'enumerable': false,
            'writable': true,
            '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 = inheritedNonEnumerablePropertySymbols( obj );
    
    console.log( symbols );