Make Object.freeze/seal/preventExtensions observable

src/object-observe.js

Index: src/object-observe.js
diff --git a/src/object-observe.js b/src/object-observe.js
index 9c7ac3889eb573b04ae6c4612dc5d4791174fda0..a4761e488098cddda2344d91777ca7b28506c11a 100644
--- a/src/object-observe.js
+++ b/src/object-observe.js
@@ -132,7 +132,8 @@ var defaultAcceptTypes = TypeMapCreateFromList([
   'updated',
   'deleted',
   'prototype',
-  'reconfigured'
+  'reconfigured',
+  'preventExtensions'
 ]);
 
 // An Observer is a registration to observe an object by a callback with
@@ -443,9 +444,20 @@ function NotifyChange(type, object, name, oldValue) {
   if (!ObjectInfoHasActiveObservers(objectInfo))
     return;
 
-  var changeRecord = (arguments.length < 4) ?
-      { type: type, object: object, name: name } :
-      { type: type, object: object, name: name, oldValue: oldValue };
+  var changeRecord;
+  if (arguments.length == 2) {

[arv (Not doing code reviews), 2013/10/29 21:58:18]

This is tangential but ES does not usually use the length of arguments.

[rafaelw, 2013/10/30 17:54:37]

(talked with arv off-line). This is internal-only API.

On 2013/10/29 21:58:18, arv wrote:

+    changeRecord = { type: type, object: object };
+  } else if (arguments.length == 3) {
+    changeRecord = { type: type, object: object, name: name };
+  } else {
+    changeRecord = {
+      type: type,
+      object: object,
+      name: name,
+      oldValue: oldValue
+    };
+  }
+
   ObjectFreeze(changeRecord);
   ObjectInfoEnqueueChangeRecord(objectInfo, changeRecord);
 }