comms.service.ts

import { Injectable } from "@angular/core";
import * as Rx from "rxjs";

@Injectable()
export class CommsService {
  // Observable with initial value set to false
  private waitingListStatus = new Rx.BehaviourSubject(false);
  
  // Updates the value of waitingListStatus
  updateWaitingList = (status: boolean) => {
    // Updates it's current value and notifies subscribers
    this.waitingListStatus.next(status);
  }
}