title: How to implement Angular 1 Form with Component and custom validation
body: <p>I want to implement an angular form that holds a custom component and that uses custom (asynchronous) validation.</p>
  
  <p>I was not able to find any documentation on how to implement that based on angular components.</p>
  
  <p>The link function used with the "normal" directive examples is not available for components. The documentation <a href="https://code.angularjs.org/1.5.1/docs/guide/forms" rel="nofollow">https://code.angularjs.org/1.5.1/docs/guide/forms</a> does only explain how to do this with directives (requiring ngModel and using it in the link function).</p>
  
  <p>How would I do this with angular components?</p>