this.image.onerror = (err) => {
   this.imageLoadSubject.complete();
 };

 constructor(event: esriMouseEvent) {
     super(event);
     this._featureSubject = new Subject();
     this.features = this._featureSubject.asObservable();
 }

                .then((directoryUser:DirectoryUser) => {
                    this._sessionUser.isAdmin = directoryUser.isAdmin;
                    this.isSignedInSubject.next(true);

                    return this._sessionUser.hostedDomain === GoogleApplicationAccount.domain;
                })

 this.get('assets/talks.json').subscribe((talks: Array<TalkModel>) => {
     this.talks = talks;
     talks.forEach((talk: TalkModel) => subject.next(talk));
     subject.complete();
 });

 .then(user => {
   logger.debug('has authenticated user', user);
   authState.next({ state: 'signedIn', user: user });
 })

 observe(): Observable<any> {
   return this._subject.asObservable();
 }

  private onEnd(event: TransitionEvent | AnimationEvent): void {

    if (!this.animationEnd.closed) {
      this.animationEnd.next(event);
    }
  }

 ngOnDestroy(): void {
   if (this.animationEnd && !this.animationEnd.closed) {
     this.animationEnd.complete();
   }
 }

 res => this.dispatcher$.next(res),