Ionic 2 admobpro reward video callback for completed video

Hi, I am currently using ionic admobpro for my app. I am having a hard trying to figure out how to get a callback for when a user has watch a reward video. Anyone know how to achieve this. I have been stuck on this for days and can’t find any helpful documentation on the event. Tried several things including document.addEventListener(‘’, () => {}); with other methods and can’t get it to work.