work in progress: observable implementation using detailed change records

example/todomvc/main.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library main;
 
 import 'dart:html';
 import 'model.dart';
 import 'package:web_ui/web_ui.dart';
 
 main() {
+  useObservers = true;
+
   // listen on changes to #hash in the URL
   // Note: listen on both popState and hashChange, because IE9 doens't support
   // history API, and it doesn't work properly on Opera 12.
   // See http://dartbug.com/5483
   updateFilters(e) {
     viewModel.showIncomplete = window.location.hash != '#/completed';
     viewModel.showDone = window.location.hash != '#/active';
     dispatch();
   }
   window.onHashChange.listen(updateFilters);
   window.onPopState.listen(updateFilters);
 }
 
 void addTodo(Event e) {
   e.preventDefault(); // don't submit the form
   var input = query('#new-todo');
   if (input.value == '') return;
   app.todos.add(new Todo(input.value));
   input.value = '';
 }