app\Product::scopeInCategories PHP Method

    public function scopeInCategories($query, $attr, $data = [])
    {
        if (count($data) > 0 && empty($data['category'])) {
            $query->whereIn($attr, $data);
        } elseif (isset($data['category'])) {
            $query->where($attr, '=', $data['category']);
        }
        return $query;
    }