Trigger `catch`/`finally` with rejected `return` promise in `async` functions

Isiah Meadows isiahmeadows at gmail.com
Sun Sep 9 20:35:22 UTC 2018


Yes, and I know it's a breaking change. And although ESLint does have
a rule banning `return await` [1], they did have to fix it to account
for the fact "fixing" the inconsistency breaks `try`/`catch`/`finally`
[2].

I'm specifically proposing it to avoid the counterintuitive behavior
that currently exists in that area, why the lint had to make the
exception in the first place.

I'm not familiar with a linter rule that addresses this issue, but it
still reads very awkwardly when it works as advertised everywhere
else.

[1]: https://eslint.org/docs/rules/no-return-await
[2]: https://github.com/eslint/eslint/issues/7581

-----

Isiah Meadows
contact at isiahmeadows.com
www.isiahmeadows.com

On Sun, Sep 9, 2018 at 3:49 PM Peter Jaszkowiak <p.jaszkow at gmail.com> wrote:
>
> So are you saying that `return promise` and `return await promise` should have identical behavior in the context of an async function?
>
> Wouldn't that be a breaking change? And isn't it trivially solvable with a linter rule?
>
> On Sun, Sep 9, 2018, 13:29 Isiah Meadows <isiahmeadows at gmail.com> wrote:
>>
>> I know this requires a bit of an exception, but I feel
>> `catch`/`finally` should trigger when a promise `return`ed from an
>> `async` function rejects. It just seems incredibly odd not to, since
>> the usual intuition is that if an error occurs during the execution of
>> a function, it's catchable by the parent via `try`/`catch`, even if
>> it's a simple `return foo(...args)`. You see that a lot with the
>> `return await foo(...args)` step necessary within `try`/`catch` blocks
>> in async functions, but that's literally the only time that idiom is
>> necessary - it's otherwise generally equivalent to `return
>> foo(...args)` mod timings, including when returning directly outside
>> them.
>>
>> Could you all in TC39 fix this to work a little more intuitively?
>>
>> -----
>>
>> Isiah Meadows
>> contact at isiahmeadows.com
>> www.isiahmeadows.com
>> _______________________________________________
>> es-discuss mailing list
>> es-discuss at mozilla.org
>> https://mail.mozilla.org/listinfo/es-discuss


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