4.0 KiB
4.0 KiB
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 anobject
'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 );