jQuery sortableWithIndexWatch - modified jquery ui sortable widget to store before and after index of moved item

jquery.sortableWithIndexWatch.js

// custom Sortable widget - gets before and after index of moved item
// https://gist.github.com/3750782
$.widget("ui.sortableWithIndexWatch", $.extend({}, $.ui.sortable.prototype, {
	
	_trigger: function() {
		
		switch(arguments[0]){
		
			case 'start':
				this.currentItem.indexStart = this.currentItem.index();
				break;
		
		
			case 'update':
				this.currentItem.indexEnd = this.currentItem.index();
				break;
		}
		
		return $.ui.sortable.prototype._trigger.apply(this, arguments);
	}
	
}));

I have a question about this... I am in my sortable receiver function like this:

$(".sortable-container").sortable({
receive: function(ev, ui){
}

Here I have $(this).data() which is giving me:

Object {ui-sortable: e.w...t.e.(...).(anonymous function)}

in this object I have ui-sortable, which has the currentItem attribute which is what I need...

How do I get to the currentItem attribute?

I have tried: $(this).data().ui-sortable and $(this).data().uiSortable but both give undefined... Thank you so much for you help!

How do I get to the currentItem attribute?

I have tried: $(this).data().ui-sortable and $(this).data().uiSortable but both give undefined

Just for a reference: use $(this).data()['ui-sortable'].currentItem in this case.