title: Angular2 ngClass with the same class but different conditions
body: <p>How to use <code>[ngClass]</code> with the same <code>.className</code> but with two different conditions?</p>
  
  <p>I tried separating them like so - but it doesn't append the class for some reason.</p>
  
  <pre><code>&lt;button class="btn" [ngClass]="{'btn-success': condition1, 'btn-success': condition2 }"&gt;My Button&lt;/button&gt;
  </code></pre>
  
  <p>Maybe something like this, its the same as above its not appending the <code>btn-success</code> class to the button.</p>
  
  <pre><code>&lt;button class="btn" [ngClass]="{'btn-success': condition1 &amp;&amp; condition2 }"&gt;My Button&lt;/button&gt;
  </code></pre>
  
  <p>Can't find anywhere if this has been done, I know you can use two different classes with one condition.</p>