controller

    public function store(Kategori $kategori, Request $request)
    {
        $validator = Validator::make($request->all(), Produk::$rule);
        if ($validator->fails()) {
            return response()->json($validator->errors());
        } else {
            $req = $request->all();
            if ($request->hasfile('gambar')) {
                foreach ($request->file('gambar') as $image) {

                    $extension = $image->getClientOriginalExtension();
                    Storage::disk('public')->put($image->getFilename() . '.' . $extension,  File::get($image));
                    $data[] = $image->getFilename() . '.' . $extension;
                }
            }
            $req['gambar'] = json_decode($data);
            $req['url_images'] = json_decode($data);
            $str = strtolower($request->judul);
            $req['slug'] = preg_replace('/\s+/', '-', $str);
            $req['user_id'] = auth()->user()->id;
            $req['kategori_id'] = $kategori->id;
            $produk = $kategori->produk()->create($req);
        }
        return response([
            'produk' => new ProdukResource($produk)
        ]);
    }