//operate on item f;
Another noticeable feature is the class construct. Classes are based on the prototype-based object oriented pattern and support inheritance methods (static and instance) and constructors.
The most interesting new feature, however, is the introduction of Object.observe(). Note that Object.observe() is going to be available only with ES7.
Object.observe() brings great performance boost over traditional dirty-checking used while implementing data binding. Testimony to this fact is that Angular team has decided to rewrite data binding implementation in Angular 2.0 using Object.observe(). As an API with great promise, Object.observe() is surely going to change a lot in the way we build client apps. You can read more here.