title: Passing Dart objects to js functions in js interop
body: <p>I've been playing around a bit with the new js interop of dart. So far everything was very straight-forward. But one thing I'm not sure about is how to deal with js stuff like this:</p>
  
  <pre><code>MathJax.Hub.Config({
    showProcessingMessages: false,
    showMathMenu: false
    .. many other different options
  });
  </code></pre>
  
  <p>I can translate the MathJax.Hub.Config part: </p>
  
  <pre><code>@JS('MathJax') external MathJaxClass get MathJax;
  class MathJaxClass {
    external HubClass get Hub;
  }
  
  @JS('MathJax.Hub')
  class HubClass {
    external void Config(options);
  }
  </code></pre>
  
  <p>But now I would like to have the <code>options</code> argument of <code>Config</code> function to be a Dart Object. I'm not sure how to do this. The only way, I can get something working is with a <code>Map</code>:</p>
  
  <pre><code>  MathJax.Hub.Config(new JsObject.jsify({
      'showProcessingMessages': false,
      'showMathMenu': false
    }));
  </code></pre>
  
  <p>But this is surely not ideal. Any ideas?</p>