title: Add class through ngClass if a disabled button is clicked
body: <p>I want to be able to add a scss class ("error") to an element, if a [disabled] button is clicked. How do i achieve this?
  <a href="https://stackoverflow.com/questions/35535350/angular2-disable-button">Angular2 disable button</a>
  the [disabled] attribute is required, so this is not a working solution.</p>
  
  <pre><code>&lt;button [disabled]="!isTermAgreed || isLoading" (click)="payForStory(paymentObject.StoryId)"&gt;
  </code></pre>
  
  <p>scss class that a span element will recieve through <code>[ngClass]</code>:</p>
  
  <pre><code>&amp;.error {
    border: 2px solid red;
  }
  </code></pre>