How to make JS validation?

Hello everyone Perhaps this is a very frequent question, but how much I am a student, I did not find a good answer, a good, in the sense, understandable. I can't figure out how to pass validator responses to JSON in Javascript. I use separate Form Request rules. Please tell me...

Controller and template codes below: Login view

@extends('layouts.account')

@section('content')
    <div class="bg-image" style="background-image: url('{{ asset('/media/sa-wallpapers/night-sf.jpg') }}');">
        <div class="row no-gutters bg-primary-op">
            <div class="hero-static col-md-6 d-flex align-items-center bg-white">
                <div class="p-3 w-100">
                    <div class="mb-3 text-center">
                        <a class="link-fx font-w700 font-size-h1" href="">
                            <small><i class='fad fa-times font-size-h4'></i></small><span class="text-muted">ID</span>
                        </a>
                        <p class="text-uppercase font-w700 font-size-sm text-muted">Авторизация</p>
                    </div>
                    <div class="row no-gutters justify-content-center">
                        <div class="col-sm-8 col-xl-6">
                            <form class="js-validation-signin" action="{{ route('xid-login') }}" method="POST" novalidate="novalidate">
                                @csrf
                                <div class="py-3">
                                    <div class="form-group">
                                        <input type="text" class="form-control form-control-lg form-control-alt" id="uLogin" name="uLogin" placeholder="{{ __('Логин') }}" value="{{ old('uLogin') }}" autocomplete="uLogin" autofocus>
                                    </div>
                                    <div class="form-group">
                                        <input type="password" class="form-control form-control-lg form-control-alt" id="uPassword" name="uPassword" placeholder="{{ __('Пароль') }}" autocomplete="current-password">
                                    </div>
                                </div>
                                <div class="form-group">
                                    <button type="submit" class="btn btn-block btn-hero-lg btn-hero-primary">
                                        <i class="fad fa-fw fa-sign-in mr-1"></i> {{ __('Войти') }}
                                    </button>
                                    <p class="mt-3 mb-0 d-lg-flex justify-content-lg-between">
                                        @if (Route::has('xid-login-recovery'))
                                            <a class="btn btn-sm btn-light d-block d-lg-inline-block mb-1" href="/login/recovery">
                                                <i class="fad fa-exclamation-triangle text-muted mr-1"></i> Забыл пароль
                                            </a>
                                        @elseif (Route::has('xid-register'))
                                            <a class="btn btn-sm btn-light d-block d-lg-inline-block mb-1" href="/register">
                                                <i class="fad fa-plus text-muted mr-1"></i> Регистрация
                                            </a>
                                        @endif
                                    </p>
                                </div>
                            </form>
                        </div>
                    </div>
                </div>
            </div>
            <div class="hero-static col-md-6 d-none d-md-flex align-items-md-center justify-content-md-center text-md-center">
                <div class="p-3">
                    <p class="display-4 font-w700 text-white mb-3">
                        Добро пожаловать в будущее!
                    </p>
                    <a class="text-white" href="">
                        <small><i class='fad fa-times font-size-sm'></i></small>STAR Project
                    </a> <i class="fad fa-copyright text-white ml-1 mr-1"></i> <span class="text-white" data-toggle="year-copy"></span>
                    <p class="text-white">Создано и разработано в <a class="font-weight-bold text-white" href="https://kdevteam.ru/" target="_blank">KDEV PRODUCTION</a></p>
                </div>
            </div>
        </div>
    </div>
@endsection

@section('js_after')
    <script src="{{ mix('/js/plugins/jquery-validation/jquery.validate.min.js') }}"></script>
    <script type="text/javascript">
        $(document).ready(function () {
            Dashmix.helpers("validation")
            $(".js-validation-signin").validate({
                rules: {
                    "uLogin": { required: true, minlength: 3, remote: {
                        url: '{{ route('xid-login') }}',
                        type: 'POST',
                        data: {
                            'uLogin': function () {
                                return $('#uLogin').val();
                            }
                        }
                    }},
                    "uPassword": { required: true, minlength: 5, remote: {
                        url: '{{ route('xid-login') }}',
                        type: 'POST'
                    }}
                },
                messages: {
                    'uLogin': { required: "Пожалуйста, введите логин", minlength: "Ваш логин должен состоять не менее чем из 3 символов", remote: 'Аккаунт с введенным логином не найден' },
                    "uPassword": { required: "Пожалуйста, укажите пароль", minlength: "Ваш пароль должен содержать не менее 5 символов" },
                },
            });
        });
    </script>
@endsection

LoginController

<?php

namespace App\Http\Controllers\Auth;

use App\Http\Controllers\Controller;
use Illuminate\Foundation\Auth\RedirectsUsers;
use Illuminate\Foundation\Auth\ThrottlesLogins;
use Illuminate\Http\Request;
use Illuminate\Http\Response;
use Illuminate\Support\Facades\Auth;
use Illuminate\Validation\ValidationException;
use App\Http\Requests\LoginRequest;

class LoginController extends Controller
{
    use RedirectsUsers, ThrottlesLogins;

    public $username;

    /**
     * LoginController constructor.
     */
    public function __construct()
    {
        $this->middleware('guest')->except('logout');
        $this->username = new LoginRequest();
    }

    /**
     * @return \Illuminate\Contracts\Foundation\Application|\Illuminate\Contracts\View\Factory|\Illuminate\View\View
     */
    public function showLoginForm()
    {
        $data = [
            'pageTemplate' => 'xid_index',
            'title' => 'xID',
            'pageUrl' => route('xid-index'),
            'pageDescription' => 'xSTAR - современный SA:MP проект, представляющий игрокам огромное количество возможностей, которые ранее казались невозможными или просто не столь интересными. Мы переворачиваем стандартные, очевидные вещи и делаем из них что-то новое, интересное для пробы. Мы уверены, что хотя бы одна вещь на нашем проекте сможет удивить лично вас.',
        ];

        return view('pages.account.login', ['data' => $data]);
    }

    /**
     * @param LoginRequest $request
     * @return Response|\Symfony\Component\HttpFoundation\Response|void
     * @throws ValidationException
     */
    public function login(LoginRequest $request)
    {
        // If the class is using the ThrottlesLogins trait, we can automatically throttle
        // the login attempts for this application. We'll key this by the username and
        // the IP address of the client making these requests into this application.
        if (method_exists($this, 'hasTooManyLoginAttempts') &&
            $this->hasTooManyLoginAttempts($request)) {
            $this->fireLockoutEvent($request);

            return $this->sendLockoutResponse($request);
        }

        if ($this->attemptLogin($request)) {
            return $this->sendLoginResponse($request);
        }

        // If the login attempt was unsuccessful we will increment the number of attempts
        // to login and redirect the user back to the login form. Of course, when this
        // user surpasses their maximum number of attempts they will get locked out.
        $this->incrementLoginAttempts($request);

        return $this->sendFailedLoginResponse($request);
    }

//    public function login(LoginRequest $request)
//    {
//        $data = DB::select('select `uSalt`, `uPassword` from `users` where `uLogin` = ?', ['ruffic']);
//        //return $request->request->filter('uPassword');
//        if ($data != null) {
//            dd($data);
//        } else {
//            echo 'LOX';
//        }
//    }

    /**
     * Attempt to log the user into the application.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return bool
     */
    protected function attemptLogin(LoginRequest $request)
    {
        return $this->guard()->attempt($this->credentials($request));
    }

    /**
     * Get the needed authorization credentials from the request.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return array
     */
    protected function credentials(LoginRequest $request)
    {
        return $request->only($this->username->username(), 'uPassword');
    }

    /**
     * Send the response after the user was authenticated.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    protected function sendLoginResponse(LoginRequest $request)
    {
        $request->session()->regenerate();

        $this->clearLoginAttempts($request);

        if ($response = $this->authenticated($request, $this->guard()->user())) {
            return $response;
        }

        return $request->wantsJson()
            ? new Response('', 204)
            : redirect()->intended($this->redirectPath());
    }

    /**
     * The user has been authenticated.
     *
     * @param  \Illuminate\Http\Request  $request
     * @param  mixed  $user
     * @return mixed
     */
    protected function authenticated(LoginRequest $request, $user)
    {
        //
    }

    /**
     * Get the failed login response instance.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Symfony\Component\HttpFoundation\Response
     *
     * @throws \Illuminate\Validation\ValidationException
     */
    protected function sendFailedLoginResponse(LoginRequest $request)
    {
        return \response()->json($request);
//        throw ValidationException::withMessages([
//            $this->username->username() => [trans('auth.failed')],
//        ]);
    }

    /**
     * Log the user out of the application.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return \Illuminate\Http\Response
     */
    public function logout(Request $request)
    {
        $this->guard()->logout();

        $request->session()->invalidate();

        $request->session()->regenerateToken();

        if ($response = $this->loggedOut($request)) {
            return $response;
        }

        return $request->wantsJson()
            ? new Response('', 204)
            : redirect('/');
    }

    /**
     * The user has logged out of the application.
     *
     * @param  \Illuminate\Http\Request  $request
     * @return mixed
     */
    protected function loggedOut(Request $request)
    {
        //
    }

    public function username() {
        return $this->username->username();
    }

    /**
     * Get the guard to be used during authentication.
     *
     * @return \Illuminate\Contracts\Auth\StatefulGuard
     */
    protected function guard()
    {
        return Auth::guard();
    }
}

And LoginRequest

<?php

namespace App\Http\Requests;

use App\Http\Controllers\Auth\LoginController;
use Illuminate\Foundation\Http\FormRequest;

class LoginRequest extends FormRequest
{

    /**
     * Determine if the user is authorized to make this request.
     *
     * @return bool
     */
    public function authorize()
    {
        return true;
    }

    /**
     * Get the validator instance for the request.
     *
     * @return \Illuminate\Validation\Validator
     */
    protected function getValidatorInstance()
    {
        $factory = $this->container->make('Illuminate\Validation\Factory');

        if (method_exists($this, 'validator'))
        {
            return $this->container->call([$this, 'validator'], compact('factory'));
        }
        return $factory->make(
            $this->json()->all(), $this->container->call([$this, 'rules']), $this->messages(), $this->attributes()
        );
    }

    /**
     * Get the validation rules that apply to the request.
     *
     * @return array
     */
    public function rules()
    {
        return [
            $this->username() => 'required|string',
            'uPassword' => 'required|string',
        ];
    }

    /**
     * @return string
     */
    public function username() {
        return 'uLogin';
    }
}

Thank you in advance!