title: Detect single or multiple file drag
body: <p>I built a file upload allowing drag-n-drop.
  I can detect when a file is being dragged over the draggable element, my problem is:
  is it possible once i detect a file being dragged over the element - if its 1 file or multiple files?
  (i want to allow single file uploads only - without allowing the user to drop multiple files).</p>
  
  <p>Thanks a lot for the help,</p>
  
  <p>Good day.</p>