title: EventEmitter: how to send the result back from the event handler to the "host" component
body: <p>I have a child component with an <code>@Output</code> parameter:</p>
  
  <pre><code>@Output updateThis: EventEmitter&lt;any&gt; = new EventEmitter&lt;any&gt;;
  </code></pre>
  
  <p>And:</p>
  
  <pre><code>this.updateThis.emit(myObject);
  </code></pre>
  
  <p>I have a parent component that handles the event. It then calls a service to update the object:</p>
  
  <pre><code>&lt;my-component (updateThis)="onUpdateThis($event)" /&gt;
  </code></pre>
  
  <p>And this is my question. After the parent component tries to modify the object, I need to signal the child component whether it could update it or not (i.e. whether the service threw an error or not).</p>
  
  <p>How could I signal the result back to the child component? One idea is to add a new property to <code>myObject</code> (i.e. <code>hasUpdateError</code>). But are there any other ways? For example, I have seen that <code>EventEmitter</code> has a subscribe method, but I wouldn't know how to use it in this case.</p>