Angular component: Can I use an Observable instead EventEmitter as @Output() property?

Question

[angular 2.4.5]

I tried and it seems to work like an EventEmitter:

• My component from outside:

  <split (visibleTransitionEnd)="log($event)"></split> 

• Inside the component:

  @Output() visibleTransitionEnd: Observable<string> observer: Observer;  constructor() {   const myObs = new Observable(observer => this.observer = observer);    this.visibleTransitionEnd = myObs     .map(x => '> ' + x + ' <')     .debounceTime(20)     .do(() => console.log('here we are!')); } 

• Then I can call inside component:

  // needed condition because if nobody subscribe 'visibleTransitionEnd' > no observer! if(this.observer) this.observer.next('test'); 

View this plunker

I like this because there's no subscription inside my component.

But is it a bad way to achieve this? What's the risk/wrong?

Is it better to use a Subject?

Answer 1

EventEmitter just extends Subject, so this is no surprise (and I also saw this already in Dart).

They use their own class to be able to alter the implementation later without breaking existing code.

So it might not be the best idea to circumvent this abstraction. If you are aware of the disadvantage and willing to accept it, you can of course do it.