title: titlecase pipe does not work with ternary operator angular2
body: <p>I have this code in component.html</p>
  
  <pre><code>&lt;div class="dashboard-table-item row"
         *ngFor="let item of itemArray"&gt;
    &lt;span&gt;{{item.value == 'user' ? 'student' : item.value  | titlecase}}&lt;/span&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>itemArray</strong> can have one of this values: admin | editor | user
  I want without modifying the <strong>itemArray</strong> output: user --> student and then titlecase it.</p>
  
  <p>I know I could change 'student' for 'Student' and it works, but my question is why does pipe(| titlecase) not work with ternary operator(condition ? 'value1' : item.value) <strong>Value1</strong></p>