Object.observe: generate change records for named properties.

src/object-observe.js

Index: src/object-observe.js
diff --git a/src/object-observe.js b/src/object-observe.js
index dcf98d84aed1e66359b2c71d8f648733f7479922..9f01acf829fe2ecc89bb8fa2885c9735cd625d67 100644
--- a/src/object-observe.js
+++ b/src/object-observe.js
@@ -68,6 +68,7 @@ function ObjectObserve(object, callback) {
       changeObservers: new InternalArray(callback)
     };
     objectInfoMap.set(object, objectInfo);
+    %SetIsObserved(object, true);
     return;
   }

[rafaelw, 2012/10/31 14:44:31]

do we have JS debug-only ASSERTS? If so, it'd be nice to ASSERT(%IsObserved)

[rossberg, 2012/11/05 17:11:08]

Unfortunately, no.

 
@@ -109,6 +110,16 @@ function EnqueueChangeRecord(changeRecord, observers) {
   }
 }
 
+function NotifyChange(type, object, name, oldValue) {
+  var objectInfo = objectInfoMap.get(object);
+  if (IS_UNDEFINED(objectInfo)) return;

[rafaelw, 2012/10/31 14:44:31]

Seems like we should CHECK() here - can we crash from JS? This should never
happen, right?

[rossberg, 2012/11/05 17:11:08]

There is no direct way to do that, but I just removed the line, so that the
access below would throw an exception. Then the !threw assertion in
JSObject::Notify would fire.

+
+  var changeRecord = { type: type, object: object, name: name };
+  if (arguments.length == 4) changeRecord.oldValue = oldValue;

[rafaelw, 2012/10/31 14:44:31]

For safety, I think that you should switch on arguments.length and create one of
two object literals. $Object is theoritically exposed and user script could have
installed an accessor on Object.prototype.oldValue.

[rossberg, 2012/11/05 17:11:08]

Done.

+  InternalObjectFreeze(changeRecord);
+  EnqueueChangeRecord(changeRecord, objectInfo.changeObservers);
+}
+
 function ObjectNotify(object, changeRecord) {
   // TODO: notifier needs to be [[THIS]]
   if (!IS_STRING(changeRecord.type))
@@ -119,7 +130,7 @@ function ObjectNotify(object, changeRecord) {
     return;
 
   var newRecord = {
-    object: object  // TODO: Needs to be 'object' retreived from notifier
+    object: object  // TODO: Needs to be 'object' retrieved from notifier
   };
   for (var prop in changeRecord) {
     if (prop === 'object')
@@ -161,4 +172,4 @@ function SetupObjectObserve() {
   ));
 }
 
-SetupObjectObserve();
+SetupObjectObserve();