Description
After #36 was merged, Array.fromAsync spec now depends on tc39/ecma262#2942, just like proposal-async-iterator-helpers.
@bakkot points out that the current spec uses AsyncFunctionStart directly rather than defining Async.fromAsync as a “built-in async function”, which is a new concept defined by tc39/ecma262#2942. (The current spec version still does require tc39/ecma262#2942’s enhancement of AsyncFunctionStart.
We probably should define Async.fromAsync as a “built-in async function object”.
Note that tc39/ecma262#2942 (comment) suggests that the final form of tc39/ecma262#2942 might still not be completely settled.
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js-choi commentedon Dec 2, 2023
As far as I can tell, all this change requires is removing steps
1,2, 3, 4, and 5, replacing them all with the sub-steps of step 3. tc39/ecma262#2942 seems to cause Array.fromAsync to implicitly be defined as a built-in async function object, whose [[Call]] method automatically creates a PromiseCapability and Abstract Closure, performs AsyncFunctionStart on them, and returns the resulting promise from PromiseCapability.I will make a pull request for these changes after #44 is reviewed and merged.
[Edit 2025-04-05: Built-in functions also are able to automatically return Completion Records, so those can also be taken out.]