AJAX POST请求不在后期路由中调用Controller方法

My code gives me 500 Internal Server error when trying to make AJAX POST request. I've done the CSRF Token part.

This is my JS code

$.ajaxSetup({
    headers: {
        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
    }
});

$('#likeBtn').on('click', function(e){

    e.preventDefault();

    //Getting urlLink and activityId - works

    $.ajax({
        type: 'POST',
        url: './mainView/postlike',
        data: {activityId : activityId},
        success: function(data){
            console.log(JSON.stringify(data));
        },
        error: function(e){
            console.log(JSON.stringify("Exception: " + e));
        }
    });
});

This is my post Route :

Route::post('/mainView/postlike', 'ActivityController@postLike')->name('postLike')->middleware('auth');

This is my controller method :

public function postLike(){
    if(Request::ajax()){
        return Response::json(Request::all());
    }
}

This is my mainView.blade.php. I didn't really want to use a form but I tried anyway.

<form id="likeForm" method="POST" action="#">
    <input class="likeToken" type="hidden" name="_token" value="{{ csrf_token() }}">
    <a id="likeBtn" data="{{ route('activity.like', ['activityId' => $activity->activity_id]) }}">
    <img src="IMG/icons/like.png" alt="likes">
    </a>{{ $activity->likes->count() }}
</form>

That being said, if I do this in my route, it outputs the message provided.

Route::post('/mainView/postlike', function(){
    if(Request::ajax()){
        echo "Hi";
    }
})->name('postLike')->middleware('auth');

It shows "Hi" when the like button is pressed

In the comments, you've posted the error message. To fix it, change this:

if(Request::ajax()){

to this:

if (request()->ajax()) {

For the second error:

response()->json(request()->all());

Also, you can inject Request class:

public function postLike(Request $request)

And use $request instead of request()