title: Angular2 Reactive forms - Set default value for form input field (input type=file)?
body: <p>i have to set default image path into formbuilder but given exception. i have also try with empty string and null.</p>
  
  <pre><code> buildForm() {
          this.userForm = this.formBuilder.group({
              location_id: this.formBuilder.control(null),
              image: this.formBuilder.control('assets/images-demo/avatars/user.png'),
          });
      }
  </code></pre>
  
  <blockquote>
    <p>ERROR DOMException: Failed to set the 'value' property on
    'HTMLInputElement': This input element accepts a filename, which may
    only be programmatically set to the empty string.</p>
  </blockquote>