An exciting new feature used with Angular 2 is the Observable. This isn't an
Angular 2 specific feature, but rather a proposed standard for managing
async data that will be included in the release of ES7. Observables open up a
continuous channel of communication in which multiple values of data can be
emitted over time. From this we get a pattern of dealing with data by using
array-like operations to parse, modify and maintain data. Angular 2 uses
observables extensively - you'll see them in the HTTP service and the event
system.