在laravel 5.4中调用未定义的方法Illuminate \ Database \ Query \ Builder :: map（）

Question

My product controller:

 public function category(Request $request, $name, $main){
          if($request->data){
            $explode_id = array_map('intval', explode(',', $request->data));
            $category_id = Category::where('name', $name)->value('id');
            if($category_id == "")
            {
              $all_categories_id = Category::pluck('id');
            }
            else
            {
            $all_categories_id = Category::where('parent_id', $category_id)->pluck('id');
            $all_categories_id->push($category_id);
            }
            $product_id = Product::where('name', 'like','%'.$main.'%')->whereIn('id', $explode_id)->pluck('id');
            $id = ProductCategory::whereIn('product_id', $product_id)->whereIn('category_id', $all_categories_id)->pluck('id');
            $products = Product::find($id); 
          }
          else{
              $category_id = Category::where('name', $name)->value('id');
              if($category_id == "")
              {
                $all_categories_id = Category::pluck('id');
              }
              else
              {
              $all_categories_id = Category::where('parent_id', $category_id)->pluck('id');
              $all_categories_id->push($category_id);
              }
              $product_id = Product::where('name', 'like','%'.$main.'%')->pluck('id');
              $id = ProductCategory::whereIn('product_id', $product_id)->whereIn('category_id', $all_categories_id)->pluck('id');
              $products = Product::find($id);
          }    

            //Categories Name in Sidebar
            $category = ProductCategory::whereIn('product_id', $id)->pluck('parent_id');
            $category_name = Category::whereIn('id', $category)->pluck('name');

            //Categories Name in dropdown
            $main_categories = Category::where('parent_id', '0')->pluck('name'); 

            $user = Auth::user();
            $directory = 'uploads/users/images/'.$user->id;
            $main_categories = Category::where('parent_id', '0')->pluck('name');
            if (is_dir($directory)) {
            $files = scandir ($directory);
            $img_file = $directory.'/'.$files[2];
            $user['front_img'] = $img_file;
            }
            $profile = $user['front_img'];
            //Product Image Mapping     
            $products->map(function ($product) {
            $directory = 'uploads/products/images/'.$product->id;
            $brand = Brand::select('name')->where('id', '=', $product->brand)->pluck('name');
            $brand_name = $brand->first(function($value, $key) {
              return $key == 'name';
            });
            if (is_dir($directory)) {
              $files = scandir ($directory);
              $img_file = $directory.'/'.$files[2];
              $product['front_img'] = $img_file;
              $product['brand'] = $brand_name;
              return $product;
            }
              return $product;
            });

          return view('pages/product', compact('main_categories', 'profile', 'products', 'name', 'category_name'));
        }

This is code in my product controller When i try to run this code it show the error here i used map() to map the products images and display it my view but why this error came ..Please any one help me..

Answer 1

That's because map() does not exist.

$products = Product::find($id);

is just short for

$products = Product::where('id', $id)->first();

So you're only getting one single Product model back. Then you're trying to call map() on it, which only exists on Collections that are returned if the results contains multiple datasets / Models. But you're explicitly asking for a single one. So you're getting Illuminate\Database\Eloquent\Model in response and then try to call map() on that. Since this method does not exist, Laravel tries to defer to Illuminate\Database\Query\Builder, and if does not find that method there, it bombs out with the above mentioned Exception.

So: There is only one $products, no need to map over it, just use it directly. Also, this would be even more clear if you called it $product instead of $products.