Proposal: parallelize consecutive awaits about proposal-async-await

[ljharb]

How would you suggest the engine be statically able to know that asyncOne does not depend on anything in asyncTwo? Here, await is statically indicating that it does depend on it.

[ljharb]

Note that this isn't just "late stage", this is finished - ie, stage 4.

Syntactic sugar for await Promise.all(…) existed very early in this proposal, but was largely rejected, as I understand it (await*)

[wheresrhys]

After giving it more thought I realised that this change could break existing code (as asyncTwo could expect some external value to be changed by asyncOne)... so for that reason I doubt this is worth considering for such a late stage proposal. Also, you're right that the static analysis is tricky as asyncOne could dynamically choose external values to change at runtime.

Perhaps there would be scope for an additional keyword which means 'await in parallel', and which allows the developer to specify which Promises can be awaited in parallel. Which would be little more than syntactic sugar around await Promise.all(), but would contribute to the sync/async symmetry that async/await aims towards.

[qfox]

Syntactic sugar for await Promise.all(…) existed very early in this proposal, but was largely rejected, as I understand it (await*)

Yep, exactly.