Group Laravel Eloquent pivot values by id

Question

I have a relational database whose models look like this:
Restaurant:

class Restaurant extends Authenticatable
{
    public function dishes()
    {
        // return $this->hasMany(Dish::class);
        return $this->belongsToMany('App\Models\Dish');
    }
}

Dish:

class Dish extends Model
{
    public function orders()
    {
        return $this->belongsToMany('App\Models\Order')->withPivot('quantity');
    }

    public function restaurant()
    {
        return $this->belongsToMany('App\Models\Restaurant');
    }
}

Order

class Order extends Model
{
    public function dishes()
    {
        return $this->belongsToMany('App\Models\Dish');
    }
}

I'm retrieving all orders belonging to the restaurant by id like so:

public function index($id)
    {
        $user_id = $id;
        $dishes = Dish::where('restaurant_id', $user_id)->get();

        foreach ($dishes as $dish => $value) {
            $orders = $value->orders;
            foreach ($orders as $order => $value) {
                $response[] = $value;
            }
        }
        return response()->json($response);
    }

This works, but I would like to group these results by order_id in some way, so that I get returned something similar to this:

 {
        "id": 28,
        "status": 1,
        "address": "Fish Street",
        "user_name": "Artyom",
        "user_surname": "Pyotrovich",
        "phone": "351 351 643 52",
        "email": "artyom@restaurant.com",
        "total": 35.8,
        "created_at": "2021-11-17T10:44:58.000000Z",
        "updated_at": "2021-11-17T10:44:58.000000Z",
        "dishes": [{
            "dish_id": 22,
            "quantity": 3
                   }, 
                   {
            "dish_id": 23,
            "quantity": 1
                  }]
    }

Is this possible by simply changing the Eloquent query or do I need to perform several operations on the result of my current query? Also interested in what is actually the best practice in these cases. Thanks in advance

Answer 1

You can use the ::with() method to get all the desired relations, this is much cleaner then a foreach rewrite.

Example:

$orders = Order::with('dishes')
    ->whereHas('dishes', function(Builder $dishes) use ($user_id) {
        $dishes->where('restaurant_id', $user_id);
    })->get();

return response()->json( $order );

Small note:

Separate the user id from the restaurant id, what if the user has multiple restaurants?