laravel 7 shopping cart tutorial

1public function addToCart($id)
2    {
3        $product = Product::find($id);
4 
5        if(!$product) {
6 
7            abort(404);
8 
9        }
10 
11        $cart = session()->get('cart');
12 
13        // if cart is empty then this the first product
14        if(!$cart) {
15 
16            $cart = [
17                    $id => [
18                        "name" => $product->name,
19                        "quantity" => 1,
20                        "price" => $product->price,
21                        "photo" => $product->photo
22                    ]
23            ];
24 
25            session()->put('cart', $cart);
26 
27            return redirect()->back()->with('success', 'Product added to cart successfully!');
28        }
29 
30        // if cart not empty then check if this product exist then increment quantity
31        if(isset($cart[$id])) {
32 
33            $cart[$id]['quantity']++;
34 
35            session()->put('cart', $cart);
36 
37            return redirect()->back()->with('success', 'Product added to cart successfully!');
38 
39        }
40 
41        // if item not exist in cart then add to cart with quantity = 1
42        $cart[$id] = [
43            "name" => $product->name,
44            "quantity" => 1,
45            "price" => $product->price,
46            "photo" => $product->photo
47        ];
48 
49        session()->put('cart', $cart);
50 
51        return redirect()->back()->with('success', 'Product added to cart successfully!');
52    }
53