# $cart->key()

> Returns the current key

- Source: `src/Toolkit/Iterator.php#L49` <https://github.com/getkirby/kirby/blob/6.0.0-beta.1/src/Toolkit/Iterator.php#L49>
- Inherited from Kirby, not part of the Merx API. See <https://getkirby.com/docs/reference>.

```php
$cart->key(): TKey|null
```

## Return type

`TKey|null`

## Parent class

`Wagnerwagner\Merx\Cart` inherited from `Kirby\Toolkit\Iterator`