Implement async iteration proposal (stage 3)

[mroch]

https://github.com/tc39/proposal-async-iteration

Stage 2, and Babel supports it as of 6.8.0.

[samwgoldman]

woah—cool

[zertosh]

Stage 3: tc39/proposals@96f8d79

[samwgoldman]

Thanks for the update. Let's do it :)

[samwgoldman]

@zertosh let me know if you run into any issues with the implementation that just landed. I'm sure I messed up somewhere :)

[BenoitZugmeyer]

Really looking forward to use this!

I just tried it quickly, a few notes:

• AsyncIterators have optional methods return and throw (well, Iterators too)
• AsyncIterators are basically a superset of Iterators, in the sense that:
  • the .next method can return Promise<IteratorResult>|IteratorResult
  • for await can iterate on both AsyncIterators and Iterators
• Symbol.asyncIterator definition is missing

[zertosh]

Thanks @samwgoldman! Looks like this is going into 0.34.0, so I'll add the transform support in Nuclide so we can take it for a test drive :)