getAllTickets()

ticket.service.ts

  getAllTickets() {
    return this._http.get(`${environment.firebase.baseUrl}/tickets.json`)
      .map(ticketsObject => Object.values(ticketsObject))
      .map(ticketsArray => ticketsArray.map(tm =>
        Observable.zip(
          Observable.of(tm),
          this._eventService.getEventById(tm.eventId),
          this._userService.getUserById(tm.sellerUserId),
          (t: TicketModel, e: EventModel, u: UserModel) => {
            return {
              ...t,
              event: e,
              seller: u
            };
          })
      ))
      .switchMap(zipStreamArray => Observable.forkJoin(zipStreamArray))
      ;
  }