title: optionall adding text at the end of an angular expression
body: <p>I have an expression that's pull data from a controller, the number of pages of a book.</p>
  
  <p>If the data exists, I want to print "X pages", where X is the value. Otherwose, I want the HTML paragraph to be blank.</p>
  
  <p>But, I can't get the syntax correct. Below, it always prints out ' pages', even if blank. How do I set up my expression? </p>
  
  <pre><code>  &lt;p&gt;{{reviewFormCtrl.book.numPages + ' pages' || "" }}&lt;/p&gt;
  </code></pre>
  
  <p>I tried doing ternary operator in the expression, but didn't have lukc</p>
  
  <pre><code> &lt;p&gt;{{(reviewFormCtrl.book.numPages &gt; 0)?{{reviewFormCtrl.book.numPages + ' pages' :"" }}&lt;/p&gt;
  </code></pre>