Ionic: get ionicScroll onScroll event

I found this thread that tells how to get the scroll event of a ionicScroll:

http://forum.ionicframework.com/t/ionicscrolldelegate-doesnt-have-a-onscroll-event/19497

$ionicScrollDelegate.getScrollView().onScroll = function () {
    console.log($ionicScrollDelegate.getScrollPosition());
};

But this doesn't work. The official doc doesn't have anything about this. Any clue?

If you simply want to listen to to the scroll event maybe the easiest way would be to use the on-scroll directive.

HTML:

<ion-content on-scroll="getScrollPosition()">
    <div class="list">
      <div class="item" ng-repeat="item in data.items">Item {{item}}</div>
    </div>
</ion-content>

JS:

$scope.getScrollPosition = function(){
   console.log($ionicScrollDelegate.getScrollPosition().top)
}

Codepen here