How to know when a Bootstrap dropdown has been closed, even if it supports no events

bootstrap-dropdown-close-wtf.js

/*
 * Quorque tu, @fat.
 * https://github.com/twitter/bootstrap/issues/1343
 */
$('[data-toggle=dropdown]').click(function() {
  var parent = $(this).parent();
  if (!parent.hasClass('open') && parent.data('close-callback'))
  { //sta per aprirsi
      parent.data('has-been-opened', true);
  }
});
var hasDropDownBeenClosed = function()
{
  $('[data-toggle=dropdown]').each(function() {
      var parent = $(this).parent();
      if (parent.data('has-been-opened') && !parent.hasClass('open') && parent.data('close-callback'))
      {
          parent.data('has-been-opened', false);
          parent.data('close-callback')();
      }
  });
  setTimeout(hasDropDownBeenClosed, checkClosedDelay);
}

var checkClosedDelay = 1000;
setTimeout(hasDropDownBeenClosed, checkClosedDelay);


$('#notifications-button').parent().data('close-callback', function() {
    console.log('just closed');
});