# nonEnumerablePropertySymbols
> Return an array of an object's own non-enumerable symbol properties.
## Usage
```javascript
var nonEnumerablePropertySymbols = require( '@stdlib/utils/nonenumerable-property-symbols' );
```
#### nonEnumerablePropertySymbols( obj )
Returns an `array` of an object's own non-enumerable symbol properties.
```javascript
var hasSymbolSupport = require( '@stdlib/assert/has-symbol-support' );
var Symbol = require( '@stdlib/symbol/ctor' );
var defineProperty = require( '@stdlib/utils/define-property' );
var obj = {};
if ( hasSymbolSupport() ) {
defineProperty( obj, Symbol( 'a' ), {
'configurable': false,
'enumerable': false,
'writable': true,
'value': 'b'
});
}
var symbols = nonEnumerablePropertySymbols( obj );
```
## Notes
- Property order is not guaranteed, as `object` property enumeration is not specified according to the [ECMAScript specification][ecma-262-for-in]. In practice, however, most engines use insertion order to sort an `object`'s properties, thus allowing for deterministic extraction.
## Examples
```javascript
var defineProperty = require( '@stdlib/utils/define-property' );
var hasSymbolSupport = require( '@stdlib/assert/has-symbol-support' );
var Symbol = require( '@stdlib/symbol/ctor' );
var nonEnumerablePropertySymbols = require( '@stdlib/utils/nonenumerable-property-symbols' );
var hasSymbols = hasSymbolSupport();
var symbols;
var obj;
function Foo() {
if ( hasSymbols ) {
defineProperty( this, Symbol( 'baz' ), {
'configurable': false,
'enumerable': false,
'writable': true,
'value': 'qux'
});
}
return this;
}
if ( hasSymbols ) {
defineProperty( Foo.prototype, Symbol( 'bip' ), {
'configurable': false,
'enumerable': false,
'writable': false,
'value': 'bop'
});
}
obj = new Foo();
symbols = nonEnumerablePropertySymbols( obj );
console.log( symbols );
```
[ecma-262-for-in]: http://www.ecma-international.org/ecma-262/5.1/#sec-12.6.4