See the original posting on DZone Python
Angular 2 does a lot of things differently from Angular 1, and one of its greatest changes is in change detection. understanding how it works has been essential, particularly when using Protractor for E2E testing. This explores how to work with zones for testing and performance. A live example of the mentioned code is here.
The biggest change in how Angular 2 handles change detection, as far as a user is concerned, is that it now happens transparently through zone.js.