title: How to include class definition through "this" keyword in Typescript?
body: <p>I'm creating a class that extend <code>HttpClient</code> then extending <code>this</code> keyword through <code>includeEventsIn</code> function, <code>includeEventsIn</code> will extend BaseService with EventAggregator type, see code <a href="https://github.com/aurelia/event-aggregator/blob/master/src/index.js#L141" rel="nofollow noreferrer">here</a>. </p>
  
  <p><strong>Question</strong></p>
  
  <ul>
  <li>How can I include <code>EventAggregator</code> methods and props in <code>BaseService</code> class along with HttpClient? </li>
  <li>What would be another approach to extend class(BaseService) with two class?</li>
  </ul>
  
  <p>Here's the code.</p>
  
  <pre><code>@transient()
  export class BaseService extends HttpClient {
      constructor() {
          super();
          includeEventsIn(this);
      }
  }
  </code></pre>