title: How to configure NgbDropdown to display the selected item from the dropdown
body: <p>In <a href="https://ng-bootstrap.github.io/#/components/dropdown" rel="noreferrer">ng-bootstrap NgbDropdown</a>, how would you display the text of the selected button so that what ever item the user selects replaces the default text initially shown?</p>
  
  <p>In the example below, the goal is to display whatever sorting option the user selects.  </p>
  
  <pre><code>&lt;div ngbDropdown class="d-inline-block"&gt;
  
    &lt;button class="btn btn-outline-primary" id="sortMenu" ngbDropdownToggle&gt;Sort by...&lt;/button&gt;
  
    &lt;div class="dropdown-menu" aria-labelledby="sortMenu"&gt;
      &lt;button class="dropdown-item"&gt;Year&lt;/button&gt;
      &lt;button class="dropdown-item"&gt;Title&lt;/button&gt;
      &lt;button class="dropdown-item"&gt;Author&lt;/button&gt;
    &lt;/div&gt;
  
  &lt;/div&gt;
  </code></pre>
  
  <p>Thanks for your help!</p>