Checking if item exists in cart

[Cannonb4ll]

Hi,

Is there a way to check wether an item has already been added to the cart, or exists?

For example, if I go:

Cart::add(15, 'Product', 1, 20.00 [
  'details' => 'Test'
]);

And re-execute this, it would just +1 the quantity, but I need to check wether the item was already added to the cart (so I can prevent it beeing added again)

Something like:

Cart::hasItem(15); (15 == the product ID or something custom sortaspeak)

Which would return true or false

[lukepolo]

Its about to be pulled in #69

Waiting for the tests to be completed.