"Reverting 30387" -- failures on IE

samples/third_party/todomvc/web/model.dart

+// Copyright (c) 2013, 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 todomvc.web.model;
+
+import 'package:polymer/polymer.dart';
+
+final appModel = new AppModel._();
+
+@reflectable
+class AppModel extends Observable {
+  final ObservableList<Todo> todos = new ObservableList<Todo>();
+  @observable int doneCount;
+  @observable int remaining;
+  @observable List<Todo> visibleTodos;
+  @observable bool hasCompleteTodos;
+
+  bool _allChecked;
+
+  AppModel._() {
+    new ListPathObserver(todos, 'done').changes.listen(_updateTodoDone);
+    windowLocation.changes.listen(_updateVisibleTodos);
+    _updateTodoDone(null);
+  }
+
+  _updateTodoDone(_) {
+    // TODO(jmesserly): we should try using Polymer Expressions and filters
+    // instead of computing so many things.
+    doneCount = todos.fold(0, (count, t) => count + (t.done ? 1 : 0));
+    hasCompleteTodos = doneCount > 0;
+    remaining = todos.length - doneCount;
+
+    _allChecked = notifyPropertyChange(const Symbol('allChecked'),
+        _allChecked, todos.length > 0 && remaining == 0);
+
+    _updateVisibleTodos(_);
+  }
+
+  _updateVisibleTodos(_) {
+    bool filterDone = null;
+    if (windowLocation.hash == '#/completed') {
+      filterDone = true;
+    } else if (windowLocation.hash == '#/active') {
+      filterDone = false;
+    }
+
+    visibleTodos = todos.where(
+        (t) => filterDone == null || t.done == filterDone)
+        .toList(growable: false);
+  }
+
+  // TODO(jmesserly): the @observable here is temporary.
+  bool get allChecked => _allChecked;
+  set allChecked(bool value) {
+    todos.forEach((t) { t.done = value; });
+  }
+
+  void clearDone() => todos.removeWhere((t) => t.done);
+}
+
+class Todo extends Observable {
+  @observable String task;
+  @observable bool done = false;
+
+  Todo(this.task);
+
+  String toString() => "$task ${done ? '(done)' : '(not done)'}";
+}