title: focus input field on value change? angular2
body: <p>I have an input field that adds class active when modalOpen = true, and this works fine. </p>
  
  <p>However, i want it to focus on the input field when this modal shows?</p>
  
  <pre><code> &lt;div [class.active]="modalOpen"&gt;
       &lt;input&gt;
   &lt;/div&gt;
  </code></pre>