anchor.diff:      return c.future;
     }
   
  -  /**
  -   * Write the enumerated children to this Firebase location. This will only
  -   * overwrite the children enumerated in the 'value' parameter and will leave
  -   * others untouched.
  -   *
  -   * The returned Future will be complete when the synchronization has
  -   * completed with the Firebase servers.
  -   */
     Future update(Map<String, dynamic> value) {
       var c = new Completer();
       var jsValue = jsify(value);
  
positive.code:   static final ServerValue = new _ServerValue();
  }
  
  /**
   * A Firebase represents a particular location in your Firebase and can be used
   * for reading or writing data to that Firebase location.
   */
  class JsFirebase extends JsQuery implements Firebase {
    Stream<Event> _onAuth;
    Disconnect _onDisconnect;
  
    /**
     * Construct a new Firebase reference from a full Firebase URL.
     */
    JsFirebase(String url) : super(url);
  
    /**
     * Construct a new Firebase reference from a JsObject.
     */
    JsFirebase.fromJsObject(JsObject obj) : super.fromJsObject(obj);
  
    /**
     * Getter for onDisconnect.
     */
    Disconnect get onDisconnect {
      if (_onDisconnect == null) {
        _onDisconnect = new JsDisconnect(_fb.callMethod('onDisconnect'));
  
negative.code:     return c.future;
    }
  
    Future createUser(Map credentials) {
      var c = new Completer();
      _fb.callMethod('createUser', [
  