title: Retrive selected value of ng-select - Angular8
body: <p>I am a novice with Angular 8.<br> 
  I created the following dropdown menu, in a component, that works very well for me:</p>
  
  <pre><code>&lt;ng-select class="w-25 p-3" placeholder="{{'author' | translate}}" [clearable]="false" [searchable]="false"&gt;
          &lt;ng-option&gt;{{'author' | translate}}&lt;/ng-option&gt;
          &lt;ng-option&gt;{{'title' | translate}}&lt;/ng-option&gt;
          &lt;ng-option&gt;{{'date' | translate}}&lt;/ng-option&gt;
  &lt;/ng-select&gt;
  </code></pre>
  
  <p>Now I would like to know how I can retrive the selected element in the <code>ts</code> file of the same component.<br>
  Thanks in advance.</p>