title: Angular 2 fail to subscribe with shared service
body: <p>I have some issues with BehaviorSubject. Here's shared service for three components:</p>
  
  <pre><code>import { Injectable } from '@angular/core';
  import { BehaviorSubject } from 'rxjs/BehaviorSubject';
  
  @Injectable()
  export class StageEndService {
  
    private stageNumber = new BehaviorSubject&lt;number&gt;(0);
    private stageNumberPassed = new BehaviorSubject&lt;number&gt;(0);
  
    stageNumber$ = this.stageNumber.asObservable();
    stageNumberPassed$ = this.stageNumber.asObservable();
  
    announceStageNumber(num) {
      this.stageNumber.last(num);
    }
  
    announceStageNumberPassed(num) {
      this.stageNumberPassed.last(num);
  
    }
  }
  </code></pre>
  
  <p>Here's first part of one of the two components that changes values in service:</p>
  
  <pre><code>import { StageEndService } from './../../../common/services/stage-end.service';
  
  @Component({
  ...
  providers: [StageEndService]
  })
  
  ...
  private value = 6;
  
  constructor (private stageEndService: StageEndService) {
  
    this.stageEndService.announceStageNumber(value);
  
  }
  </code></pre>
  
  <p>Second component is similar, but changes value of stageNumberPassed.</p>
  
  <p>In my last component I'm trying to subscribe but fail (console.log returns 0):</p>
  
  <pre><code>import { StageEndService } from './../../../common/services/stage-end.service';
  
  // there's no provider here since it's not necessary if I'm correct
  
   constructor(private stageEndService: StageEndService) {}
  
  ngOnInit() {
    this.stageNumberSubscription = this.recruitmentEndService.stageNumber$.subscribe(response =&gt; {
    this.stageNumber = response;
  });
  </code></pre>
  
  <p>No idea where's the problem. When I log values passed to function in service it  returns correct numbers. Don't know if that matters but just in case: last component (where I'm trying to subscribe) is grand-grandchildren of the first component where I'm setting new value for the first time.</p>