How to return value inside subscribe Angular 4

Question

I\'m new to observables in angular. I have a problem wanting to return a value inside a subscribe method. I have the following method (getFirebaseData(idForm:string):o

Answer 1

You can't directly return totalQuestions like that, you need to use a subject to achieve that.

getTotalQuestions(idForm:string): Observable {
let totalQuestions:number;
var subject = new Subject();
this.getFirebaseData(idForm+"/Metadatos")
.subscribe(items => {
    items.map(item => {

      totalQuestions=item.Total;
      console.log(totalQuestions);
      subject.next(totalQuestions);
    });
  }
);
  return subject.asObservable();
}

Usage: getTotalQuestion(idForm).subscribe((r)=>console.log(r))