Converted Observatory nav-menu element

runtime/observatory/lib/src/elements/nav/menu.dart

+// Copyright (c) 2016, 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.
+
+import 'dart:html';
+import 'dart:async';
+import 'package:observatory/src/elements/helpers/tag.dart';
+import 'package:observatory/src/elements/helpers/rendering_scheduler.dart';
+
+class NavMenuElement extends HtmlElement implements Renderable {
+  static final StyleElement _style = () {
+      var style = new StyleElement();
+      style.text = '''li.nav-menu_label, li.nav-menu_spacer {
+                        float: left;
+                      }
+                      li.nav-menu_label > a, li.nav-menu_spacer {
+                        display: block;
+                        padding: 12px 8px;
+                        color: White;
+                        text-decoration: none;
+                      }
+                      li.nav-menu_label:hover {
+                        background: #455;
+                      }
+                      li.nav-menu_label > ul {
+                        display: none;
+                        position: absolute;
+                        top: 98%;
+                        list-style: none;
+                        margin: 0;
+                        padding: 0;
+                        width: auto;
+                        z-index: 1000;
+                        font: 400 16px \'Montserrat\', sans-serif;
+                        color: white;
+                        background: #567;
+                      }
+                      li.nav-menu_label > ul:after {
+                        content: ""; clear: both; display: block;
+                      }
+                      li.nav-menu_label:hover > ul {
+                        display: block;
+                      }''';
+      return style;
+  }();
+
+  static const tag = const Tag<NavMenuElement>('nav-menu-wrapped');
+
+  RenderingScheduler _r;
+
+  Stream<RenderedEvent<NavMenuElement>> get onRendered => _r.onRendered;
+
+  String _label;
+  String _link;
+  bool _last;
+  String get label => _label;
+  String get link => _link;
+  bool get last => _last;
+  set label(String value) {
+    if (_label != value) {
+      _label = value;
+      _r.dirty();
+    } else {
+      _r.scheduleNotification();
+    }
+  }
+  set link(String value) {
+    if (_link != value) {
+      _link = value;
+      _r.dirty();
+    } else {
+      _r.scheduleNotification();
+    }
+  }
+  set last(bool value) {
+    if (_last != value) {
+      _last = value;
+      _r.dirty();
+    } else {
+      _r.scheduleNotification();
+    }
+  }
+
+
+  factory NavMenuElement(String label, {String link, bool last: false,
+                             RenderingQueue queue}) {
+    assert(label != null);
+    assert(last != null);
+    NavMenuElement e = document.createElement(tag.name);
+    e._r = new RenderingScheduler(e, queue: queue);
+    e._label = label;
+    e._link = link;
+    e._last = last;
+    return e;
+  }
+
+  NavMenuElement.created() : super.created() { createShadowRoot(); }
+
+  @override
+  void attached() { super.attached(); _r.enable(); }
+
+  @override
+  void detached() {
+    super.detached(); _r.disable(notify: true);
+    shadowRoot.children = [];
+  }
+
+  void render() {
+    List<Element> children = [
+      _style.clone(true),
+      new LIElement()
+        ..classes = ['nav-menu_label']
+        ..children = [
+          new AnchorElement(href: '#$link')
+            ..text = label,
+          new UListElement()
+            ..children = [
+              new ContentElement()
+            ]
+        ]
+    ];
+    if (!last) {
+      children.add(
+        new LIElement()
+          ..classes = ['nav-menu_spacer']
+          ..innerHtml = '&gt;'
+      );
+    }
+    shadowRoot.children = children;
+  }
+}