You can see the latest proposals on the tc39/ecma262 GitHub repository.
A channel for feedback on ECMAScript standards is es-discuss.
These ES2016 features are implemented:
These ES2017 features are implemented:
- Async Functions
- Trailing commas in function parameter lists (Firefox 52)
This section needs to be updated to reflect current changes. (May 2019)
Experimental new features
The following features are already implemented, but only available in the Firefox Nightly channel and not yet included in a draft edition of an ECMAScript specification.
Additions to the
New TypedObject objects
- Based on Typed Objects draft, and exposed via a global
TypedObject.ArrayType. This feature is non-standard and not documented.