laravel select2错误undefined不是一个函数

i am get json encoded data in id text pair results: [{id:2, text:3}, {id:21, text:654}, {id:23, text:12343}, {id:24, text:4536}, {id:28, text:987},…] total: 13

my select2 code

$("#model_no_search").select2({
    ajax: {
        url: 'get_model_no',
        dataType: "json",
        type: "POST",
        quietMillis: 500,
        data: function (term, page) {
            return {
                str:term
            };
        },
        results: function (data, page) {
            console.log(data.results);
            return { results:  data.results };
        }
    },
    allowClear: true,
});

get_model_no function

public function get_model_no($str=0) {
    $data['total'] = Bag_model::leftJoin('category', 'bag.cat_id', '=', 'category.id')
                ->select('model_no AS text','model_id AS id')->get()->count();

    $data['results'] = Bag_model::leftJoin('category', 'bag.cat_id', '=', 'category.id')
                ->select('model_id AS id','model_no AS text')->get()->toArray();

    echo json_encode($data);
}

in route

Route::post('get_model_no', 'Bag@get_model_no');

your help is appriciated. thanks in advance.