title: Angular form updateValueAndValidity of all children controls
body: <p>In my Angular 4 app, I have a form with several controls.</p>
  
  <p>At some points I need to force the update of their validity, so I'm doing:</p>
  
  <pre><code>this.form.get('control1').updateValueAndValidity();
  this.form.get('control2').updateValueAndValidity();
  this.form.get('control3').updateValueAndValidity();
  // and so on....
  </code></pre>
  
  <p>and then:</p>
  
  <pre><code>this.form.updateValueAndValidity();
  </code></pre>
  
  <p>this works fine.</p>
  
  <p>However I was wondering if there is a better way to accomplish the same thing, by just calling one method on the parent form.</p>
  
  <p>According to its <a href="https://angular.io/api/forms/AbstractControl#updateValueAndValidity" rel="noreferrer">documentation</a>, the <code>updateValueAndValidity()</code> method:</p>
  
  <blockquote>
    <p>By default, it will also update the value and validity of its <strong>ancestors</strong>.</p>
  </blockquote>
  
  <p>but in my case I need to update the value and validity of its <strong>descendants</strong>. So I can get rid of many lines of code.</p>