You can see the latest proposals on the tc39/ecma262 GitHub repository.
A channel for feedback on ECMAScript standards is es-discuss.
Below is a list of features in ES2016+ and what version of Firefox they were implemented in.
- Async Functions
- Trailing commas in function parameter lists (Firefox 52)
- Spread in Object Literals and Rest parameters (Firefox 55)
for await...of(Firefox 57)
Global_Objects/SharedArrayBuffer(Firefox 57, with flags)
Global_Objects/RegExp/dotAll(not yet implemented; in other browsers)
- RegExp Lookbehind Assertions (not yet implemented; in other browsers)
- RegExp Unicode Property Escapes (not yet implemented; in other browsers)
- RegExp Named Capture Groups (not yet implemented; in other browsers)
This is the current ES.Next version.
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.
- Based on Typed Objects draft, and exposed via a global
TypedObject.ArrayType. This feature is non-standard and not documented.