http://mcgivery.com/understanding-ionic-2-class/
"In Ionic 2, classes are at the center of everything thanks to ES6. Everything is now a class. For someone coming from other object oriented languages, they wil feel right at home with classes. For anyone who comes from JavaScript, there may be some mind-wrapping-around that needs to happen to get to the point of comfort with this new paradigm.
In this article, we’ll take a look at the basics of writing classes."