eventController interop with polymer.js

pkg/polymer/lib/src/instance.dart

Index: pkg/polymer/lib/src/instance.dart
diff --git a/pkg/polymer/lib/src/instance.dart b/pkg/polymer/lib/src/instance.dart
index 7838acaf525a51455ae44c376fc61283102b89f6..1c1f7299de9779d4a71361647f27ed023d920399 100644
--- a/pkg/polymer/lib/src/instance.dart
+++ b/pkg/polymer/lib/src/instance.dart
@@ -182,12 +182,16 @@ abstract class Polymer implements Element, Observable, NodeBindExtension {
   CompoundObserver _propertyObserver;
   bool _readied = false;
 
+  JsObject _jsElem;
+
   /// Returns the object that should be used as the event controller for
   /// event bindings in this element's template. If set, this will override the
   /// normal controller lookup.
-  // TODO(jmesserly): type seems wrong here? I'm guessing this should be any
-  // kind of model object. Also, should it be writable by anyone?
-  Polymer eventController;
+  // TODO(jmesserly): we need to use a JS-writable property as our backing
+  // store, because of elements such as:
+  // https://github.com/Polymer/core-overlay/blob/eeb14853/core-overlay-layer.html#L78
+  get eventController => _jsElem['eventController'];
+  set eventController(value) { _jsElem['eventController'] = value; }

[Siggi Cherem (dart-lang), 2014/06/18 01:51:42]

woah!

Should we add the type annotation here? Mainly I'm wondering about what the old
comment used to say.

[Jennifer Messerly, 2014/06/18 02:18:47]

Hmmm. We could put back Element, which is what PolymerEventBindings will
type-assert. But I removed it to address that TODO :). Ultimately any kind of
model should be allowed, not just a custom element, although that limitation is
convenient at the moment since it means it's serializable to JS.

Generally though, I'm finding dynamic works better with interop-y code. Might as
well take advantage of optional types where they make sense.

 
   bool get hasBeenAttached => _hasBeenAttached;
   bool _hasBeenAttached = false;
@@ -263,6 +267,7 @@ abstract class Polymer implements Element, Observable, NodeBindExtension {
       window.console.warn('Element already prepared: $_name');
       return;
     }
+    _initJsObject();
     // Dart note: get the corresponding <polymer-element> declaration.
     _element = _getDeclaration(_name);
     // install property storage
@@ -277,6 +282,12 @@ abstract class Polymer implements Element, Observable, NodeBindExtension {
     addHostListeners();
   }
 
+  /// Initialize JS interop for this element. For now we just initialize the
+  // JsObject, but in the future we could also initialize JS APIs here.
+  _initJsObject() {
+    _jsElem = new JsObject.fromBrowserObject(this);
+  }
+
   makeElementReady() {
     if (_readied) return;
     _readied = true;