Custom Shopping Cart class that calculates weight of items in the cart

Cart.php

<?php

namespace App\Helpers;

use Darryldecode\Cart\Facades\CartFacade;

class Cart
{
    /**
     * @var bool|CartFacade
     */
    private $cart;

    public function __construct()
    {
        $this->cart = CartFacade::session(config('shopping_cart.default_cart_session_key'));
    }

    /**
     * get cart sub total with item conditions applied to each condition.
     *
     * @return float
     */
    public function getSubtotalWithItemConditions()
    {
        $cart = $this->cart->getContent();

        return $cart->sum(function ($item) {
            return $item->getPriceSumWithConditions(false);
        });
    }

    /**
     * get total weight of items in the cart.
     *
     * @return int
     */
    public function getTotalWeight()
    {
        $items = $this->cart->getContent();

        if ($items->isEmpty()) {
            return 0;
        }

        return $items->sum(function ($item) {
            return $item->attributes['weight'] * $item['quantity'];
        });
    }

    /**
     * Get coupon conditions applied to the cart.
     *
     * @return \Darryldecode\Cart\CartCollection
     */
    public function getCouponConditions()
    {
        return $this->cart->getContent()
            ->pluck('conditions')
            ->flatten()
            ->filter(function ($value) {
                return $value->getType() == 'coupon';
            });
    }

    /**
     * Get the VAT applied on the cart.
     *
     * @return int
     */
    public function getVatCondition()
    {
        $condition = $this->cart->getCondition('VAT');

        return is_null($condition) ? 0 : $condition->getCalculatedValue($this->cart->getSubtotal());
    }
}

ShoppingCartController.php

<?php

namespace App\Http\Controllers;

use App\User;
use App\Product;
use App\Setting;
use App\Helpers\Cart;
use Illuminate\Http\Request;
use Darryldecode\Cart\CartCondition;
use Darryldecode\Cart\Facades\CartFacade;

class ShoppingCartController extends Controller
{
    /**
     * @var bool|CartFacade
     */
    private $cart;

    public function __construct()
    {
        $this->cart = CartFacade::session(config('shopping_cart.default_cart_session_key'));
    }

    /**
     * Add a product to the shopping cart.
     *
     * @param Request $request
     * @param Product $product
     *
     * @throws \Darryldecode\Cart\Exceptions\InvalidConditionException
     *
     * @return \Illuminate\Http\RedirectResponse
     */
    public function store(Request $request, Product $product)
    {
        $request->validate(['quantity' => ['sometimes', 'integer', 'min:1']]);

        $attributes = ['weight' => $product->weight];

        $vat = Setting::first()->cart_vat;

        $tax = new CartCondition([
            'name'   => 'VAT',
            'type'   => 'tax',
            'target' => 'total',
            'value'  => "{$vat}%",
            'order'  => 1,
        ]);

        $this->cart->condition([$tax]);

        $discount = new CartCondition([
            'name'  => 'Category and Subcategory discount',
            'type'  => 'discount',
            'value' => "-{$product->discount}%",
        ]);

        $this->cart->add([
            'id'              => $product->id,
            'name'            => $product->name,
            'price'           => $product->price,
            'quantity'        => $request->filled('quantity') ? (int) $request->quantity : 1,
            'attributes'      => $attributes,
            'conditions'      => [$discount], // do not remove brackets as it breaks adding more conditions to item
            'associatedModel' => $product,
        ]);

        $route = route('cart.index');

        toast("Product added to cart. <a href=\"{$route}\"> View Cart</a>", 'success');

        return redirect()->back();
    }

    /**
     * Update the specified resource in storage.
     *
     * @param \Illuminate\Http\Request $request
     * @param int                      $id
     * @param Cart                     $cart
     *
     * @return \Illuminate\Http\JsonResponse|\Illuminate\Http\Response
     */
    public function update(Request $request, $id, Cart $cart)
    {
        $request->validate(['quantity' => ['required', 'integer', 'min:1']]);

        $this->cart->update($id, [
            'quantity' => [
                'relative' => false,
                'value'    => $request->input('quantity'),
            ],
        ]);

        return response()->json([
            'data' => [
                'weight'   => $cart->getTotalWeight(),
                'tax'      => $cart->getVatCondition(),
                'total'    => $this->cart->getTotal(),
                'subtotal' => $this->cart->getSubTotal(),
                'count'    => $this->cart->getContent()->count(),
            ],
        ], 200);
    }

}

This is great