title: Listen to variable update in service Angular2/4
body: <p>I have some object in global service. One of component uses socket and updates this object, but other component doesn't get any changes.</p>
  
  <p>PlanService</p>
  
  <pre><code>@Injectable()
  export class PlanService {
  
      private subject = new Subject&lt;any&gt;();
      private planSubject = new Subject&lt;any&gt;();
      public planList;
      constructor( private socket: SocketClientService) { 
             this.socket.on('plan');
  
      }
  </code></pre>
  
  <p>First Component update planList </p>
  
  <pre><code>constructor(
    private planService: PlanService,
      private socket: SocketClientService,
      public projectsService: ProjectsService,
      private groupsService: GroupsService,
      private calendarShare: CalendarDateShareService,
  
  ) {
      this.socket.on('plan');
      this.planService.getUserBusy().distinctUntilChanged().subscribe((data) =&gt; {
          planService.planList = data;  /* update */
  
      });
  </code></pre>
  
  <p>Second Component should listen and update</p>
  
  <p>planService.planList</p>
  
  <p>I am new in Angular 2</p>