jQuery UI – draggable 'snap' event

I'm looking a way to binding the snap event.

When I'm dragging an element over my surface and the draggable element is snapped to a declared snap position I want to trigger an event.

Something like this:

$(".drag").draggable({
  snap: ".grid",
  snaped: function( event, ui ) {}
});

Bonus point: with a reference to the .grid element where the draggable element was snapped.