[blink-dev: FYI]
We have updated our staged implementation of ES6 classes to match the recent changes in ES6 spec draft.
We are happy to report that these changes enabled us to implement the spec in its entirety (almost; see limitations below), most critically including subclassing of built-ins and exotic objects.
IE has classes in preview release [1]. No other browser currently ships classes (Mozilla bug [2]).
V8 implementation of classes is up-to-date with the latest ES6 draft spec.
Limitations:
- Classes are dependent on lexical declarations. Since the latter are currently only supported in strict mode, we currently only support classes in strict mode as well.
- At this time we do not support 'new.target' JS syntax. Implementation of that will follow under a separate intent-to-implement/intent-to-ship. (We stress that this is not due to any deficiencies or issues with the specification or semantics - our implementation is just not ready yet)