Doctrine 2 ArrayCollection - how to find and modify a specific element - php

Question

I have a Cart entity that contains an ArrayCollection of CartItems. The relationship in code -
Cart.php:
class Cart
{
/**
* #ORM\OneToMany(targetEntity="CartItem", mappedBy="cart")
*/
private $cartItems;
public function __construct(User $user)
{
$this->cartItems = new ArrayCollection();
}
}
CartItems are essentially a DB pointer (for lack of a better term) to a Product entity, with an additional quantity field.
CartItem.php:
class CartItem
{
/**
* #ORM\ManyToOne(targetEntity="Cart", inversedBy="cartItems")
*/
private $cart;
/**
* #ORM\OneToOne(targetEntity="Product")
*/
private $product;
/**
* #ORM\Column(type="float")
*
* #Assert\NotBlank(message="You must specify how much of the item you wish to buy")
* #Assert\Regex(pattern="/^\d+(\.\d{1,2})?$/", message="The quantity must be a number")
*/
private $quantity;
}
In my app, when a user wants to add a Product to their Cart, I want to check to see if that particular Product is already one of the CartItems. If so, I want to increase the quantity, otherwise add it to the collection. I'm not exactly sure how to do this.
ArrayCollection methods exists and contains simply return true/false. Given my setup, I'm not sure what I'd use as a key for the collection.
Any suggestions?

Answer 1

You can filter CartItems for new Product. If filtered CartItems is not empty increase the quantity, otherwise add new CartItem.
$newProduct // Product Object
$cartItems = $cart->getCartItems()->filter(function(CartItem $cartItem) (use $newProduct) {
return $cartItem->getProduct() === $newProduct;
});
if ($cartItems->count()) {
foreach ($cartItems as $cartItem) {
$cartItem->setQuantity($cartItem->getQuantity() + 1);
}
} else {
$cart->addCartItem(
(new CartItem())
->setProduct($newProduct)
->setQuantity(1)
);
}