title: Observable closed on error
body: <p>I have an issue with Observable in Angular 2.</p>
  
  <p>I subscribe my component to an observable, then when my service has new value, my component is notified.<br>
  Problem is when the observer push an error, like an HTTP error, my observable is closed, so my component is no more notified.</p>
  
  <p><strong>Question</strong><br>
  How can I do to make my component continue listening my service even when I have an error ?</p>
  
  <p><strong>Example</strong><br>
  Here an <a href="https://plnkr.co/edit/RaG7WiGgKItGUMYPjm03?p=preview" rel="nofollow noreferrer">example</a></p>
  
  <p>Here my code :</p>
  
  <p><strong>Component</strong></p>
  
  <pre><code>constructor(private appService: AppService) {
      //I subscribe my component to an observable
      this.appService.commentsObservable.subscribe((comments) =&gt; {
          console.log(comments);
      }, (err) =&gt; {
          console.log(err);
      });
  }
  
  getComments() {
      //I ask the service to pull some comments
      this.appService.getComments()
  }
  </code></pre>
  
  <p><strong>Service</strong></p>
  
  <pre><code>private commentsObserver: Observer&lt;any&gt;;
  commentsObservable: Observable&lt;any&gt;;
  
  constructor() {
      this.commentsObservable = new Observable((observer) =&gt; {
          this.commentsObserver = observer;
      });
  }
  
  getComments() {
      setTimeout(() =&gt; {
          //You will see the result displayed by the component
          this.commentsObserver.next([]);
      }, 0);
  
      setTimeout(() =&gt; {
          //You will see the result displayed by the component
          this.commentsObserver.next([]);
      }, 500);
  
      setTimeout(() =&gt; {
          //You will see the error displayed by the component
          this.commentsObserver.error({_body: 'Nice errroorr'});
      }, 1000);
  
      setTimeout(() =&gt; {
          //You won't see this one, why ?
          this.commentsObserver.next([]); 
      }, 1500);
  }
  </code></pre>