title: Format date in knockout
body: <p>I have current date in javascript like below:</p>
  
  <pre><code>self.currentDate = ko.observable(new Date());
  </code></pre>
  
  <p>I want to format the date in yyyy-mm-dd and use inside Sammy like below:</p>
  
  <pre><code>this.get('', function () { this.app.runRoute('get', '#'+self.currentDate()) });
  </code></pre>
  
  <p>There are so many long process to do it. But is there any way to do it easily. Or can i use it inside document.ready function and used it here. </p>