title: Filter array in template Angular2
body: <p>I'm trying to make simple template but I came across little issue. I want to print the number of uncompleted task in my todo list, but can't filter them inside template. I have this:</p>
  
  <pre><code>&lt;span class="todo-count"&gt;&lt;strong&gt;{{todos.length}}&lt;/strong&gt; left&lt;/span&gt;
  </code></pre>
  
  <p>But I want to filter this todos to count just ones that have status completed set to false:</p>
  
  <pre><code>&lt;span class="todo-count"&gt;&lt;strong&gt;{{todos.filter(t =&gt; !t.complete).length}}&lt;/strong&gt; left&lt;/span&gt;
  </code></pre>
  
  <p>But this isn't working. How can I achieve that?</p>