Is there a way to emit event in angular2 that can be listened to in entire application? Like we had in AngularJS using $rootScope.broadcast and emit. Can this same thing be achieved in angular2? I read about @Output() and EventEmitter() and implemented it but it restricts only the parent to listen to the event emmitted by child.
I read about BehaviorSubject being one of the ways to do this. Is that the right approach? Any other solution for this?
In Angular2 there is no global scope. There are only components and services.
With services you can define their scope by the place you provide them. If you provide one in @NgModule({providers: ...}) (or in an imported module) it becomes globally avialable. If you provide it at a component, it is only available to this component and its children.
For examples how to use shared services see https://github.com/dart-lang/sdk/issues/27637
You can also dispatch a bubbling DOM event like shown in in Angular2 how to know when ANY form input field lost focus
Events emitted with @Output() someOutput:EventEmitter = new EventEmitter(); don't bubble.
来源：https://stackoverflow.com/questions/40889320/emit-and-broadcast-events-throughout-application-in-angular