Access formData in Laravel

JS:

var file = e.originalEvent.dataTransfer.files[0];
var formData  = new FormData();

formData.append('file', file)

$.ajaxSetup ({
    processData: false
});

$.post('/addaltproduct',
    {
        file: formData
    },
    function (data) {
        console.log(data);
}).fail(function (xhr, textStatus, errorThrown) {
        console.log(xhr.responseText);
});

Controller:

if ($request->file('file')) {
    return 'OK';
}
return 'No file';

In return I always get 'No file', though if I run console.log(formData.get('file')) in JS it shows me the data.