title: How to fire Angular 5 async validator onblur for FormGroup
body: <p>I am using Angular version 5.0.1 and I'm trying to fire an <code>AsyncValidator</code> on a <code>FormGroup</code> on a blur event on one of the <code>FormControls</code> in the <code>FormGroup</code>. </p>
  
  <p>I can get <code>onBlur</code> to work on a form control using the following:</p>
  
  <pre class="lang-js prettyprint-override"><code>name: ['', {updateOn: 'blur'}]
  </code></pre>
  
  <p>However, when I try to apply it to a <code>FormGroup</code> it doesn't work. </p>
  
  <p>Is it possible to only fire an <code>AsyncValidator onBlur</code> on a <code>FormGroup</code>, and if not, what is the best way to execute the validator only when the user has finished entering data? </p>
  
  <p>My only other option at the moment is to us some sort of debounce wrapper for my validator. </p>
  
  <p>Just reading through <a href="https://blog.angular.io/version-5-0-0-of-angular-now-available-37e414935ced" rel="noreferrer">here</a> and it appears I should be able to use <code>updateOn: 'blur'</code> for a form group. </p>
  
  <blockquote>
    <p>After
    new FormGroup(value, {updateOn: 'blur'}));
    new FormControl(value, {updateOn: 'blur', asyncValidators: [myValidator]})</p>
  </blockquote>