# propertySymbolsIn
> Return an array of an object's own and inherited [symbol][@stdlib/symbol/ctor] properties.
## Usage
```javascript
var propertySymbolsIn = require( '@stdlib/utils/property-symbols-in' );
```
#### propertySymbolsIn( obj )
Returns an `array` of an object's own and inherited [symbol][@stdlib/symbol/ctor] properties.
```javascript
var symbols = propertySymbolsIn( [] );
```
## Notes
- In contrast to the built-in `Object.getOwnPropertySymbols()`, if provided `null` or `undefined`, the function returns an empty `array`, rather than throwing an error.
## Examples
```javascript
var hasSymbolSupport = require( '@stdlib/assert/has-symbol-support' );
var Symbol = require( '@stdlib/symbol/ctor' );
var propertySymbolsIn = require( '@stdlib/utils/property-symbols-in' );
var hasSymbols;
var symbols;
var obj;
hasSymbols = hasSymbolSupport();
function Foo() {
if ( hasSymbols ) {
this[ Symbol( 'beep' ) ] = 'boop';
}
return this;
}
if ( hasSymbols ) {
Foo.prototype[ Symbol( 'foo' ) ] = 'bar';
}
obj = new Foo();
symbols = propertySymbolsIn( obj );
console.log( symbols );
```
[@stdlib/symbol/ctor]: https://www.npmjs.com/package/@stdlib/symbol-ctor