PHP not receiving POST array when it is sent empty from jQuery

I'm using Laravel. When I dd($request->all()) it prints data only when the array is not empty i.e. Array['some-value']. When I console.log(data) in jQuery, it logs in console that it is an array but just doesn't have any value inside. However in Laravel I can't get that empty array, but I can get it when it has value. I want to send array even if it's empty.

How can I do that?

UPDATE

HTML:

<ul>
    <!-- It sends but doesn't show in Laravel when this active class below is not exists -->
    <li class="active" data-motion="1">motion 1</li>
    <li data-motion="2">motion 2</li>
    <li data-motion="3">motion 3</li>
</ul>

jQuery:

$.each($('ul li.active'), function(index, motion) {
    motion = $(motion).attr('data-motion');
    params['motions'].push(motion);
});

// it shows the empty array when that active class is not there,
// which is the one I want to get in Laravel too.
consol.log(params);

$.ajax({
    url: '/my-motions',
    type: 'PUT',
    dataType: 'json',
    data: params,
    success: function(response) {
        params = [];
    },
    error: function(error) {
        //
    }
});

Laravel:

public function myFunc(Request $request)
{
    $data = $request->all();
    dd($data);
    // The result: nothing
    // What I want: array:0 [] 
}