Laravel 5.4 form validation with ajax

I have a problem when it comes to displaying the error messages of the form with ajax, by traditional http everything goes well but when I do it by ajax and I force an error in the form it tells me 422 Unprocessable Entity as a response but it does not show me the error messages as if it were normal http.

If the form is fine, continue with the controller code, I put a response below to check if it was received correctly by ajax and it did indeed respond to the message.

if ($request->ajax()) {
        return response()->json(['mensaje'=>'validacion pasada wey']);
    }

I reiterate, for normal http everything works fine and it shows me the corresponding validation messages, for example: name cannot be less than 3 characters.

I went through the documentation and quote this part: For a traditional HTTP request, a redirect response will be generated, while a JSON response will be sent for AJAX requests.

I leave my ajax code with which I have been testing the responses:

$('#btn_main').on('click',function(e){
        e.preventDefault();
        var action = $('#mainform').attr('action');
        var method = $('#mainform').attr('method');

        $.ajax({
        beforeSend:function(){
            console.log('before send ok');
        },
        url: action,
        type: method,
        data: $('#mainform').serialize(),
        dataType:'json',

        success:function(respuesta){
            $.each(respuesta,function(name,value){
                console.log('name: '+ name + '\n'+ 'value: '+ value);
            });
        },

        error:function(jqXHR,estado,error){
            console.log('estado error: ' + estado);
            console.log('error de error: ' + error);
        },

        complete:function(jqXHR,estado){
            console.log('estado complete: ' + estado);
        },
        timeout:10000
        });
    });

The way I am validating in the controller is as follows:

$this->validate($request,[
        'tracking' => 'min:3',
        'date' => 'min:6|required'
    ]); 

Do I need to add something extra to the validation in the controller so that it gives me the corresponding response in json?

So I'm showing the errors but I guess if it gives me a json response I'll have to add them with jquery.

@if(count($errors)>0)
    <ul class="alert alert-danger">
    @foreach($errors->all() as $error)
        <li>{{ $error }}</li>
    @endforeach
    </ul>
@endif