title: Knockout "If viewModel property contains 'some text'"
body: <p>I was relying on the answer here <a href="https://stackoverflow.com/questions/22876740/how-to-check-contain-in-knockout">How to check contain in knockout</a> but it seems to be for an outdated version of Knockout. I'm trying to do something like:</p>
  
  <pre><code>&lt;li&gt;
     &lt;span data-bind="text: Subject"&gt;&lt;/span&gt;
     &lt;!-- ko if: Subject.contains('Important') --&gt;
        &lt;i class="fa fa-exclamation-triangle"&gt;&lt;/i&gt;
     &lt;!-- /ko --&gt;
  &lt;/li&gt;
  </code></pre>
  
  <p>Where the fontawesome icon is appended to the ko Subject text if that Subject text contains the word 'Important'. This however does not work ('contains' is not a function), and I am struggling to find an "up-to-date" solution.</p>