ng2-bootstrap-base-modified/demo/src/app/components/+dropdown/demos/disabled-menu/disabled-menu.html

Native Angular Bootstrap Components Typeahead modified

<div class="btn-group" dropdown>
  <button id="single-button" type="button" class="btn btn-primary" dropdownToggle [disabled]="disabled">
    Button dropdown <span class="caret"></span>
  </button>
  <ul dropdownMenu role="menu" aria-labelledby="single-button">
    <li role="menuitem"><a class="dropdown-item" href="#">Action</a></li>
    <li role="menuitem"><a class="dropdown-item" href="#">Another action</a></li>
    <li role="menuitem"><a class="dropdown-item" href="#">Something else here</a></li>
    <li class="divider dropdown-divider"></li>
    <li role="menuitem"><a class="dropdown-item" href="#">Separated link</a></li>
  </ul>
</div>
<button type="button" class="btn btn-warning" (click)="disabled = !disabled">Enable/Disable</button>