for await of syntax doesn't work with --experimental-repl-await

Version: v10.9.0
Platform: Windows 10 Pro 10.0.17134 x64
Subsystem: REPL

The REPL is working great with regular await, but doesn't seem to be able to handle the new for await of syntax that was introduced as part of the async-iteration spec.

for await of works when wrapping the call with an async function, it only fails if used at the top level.

This fails:

$ node --experimental-repl-await
> for await (let i of [1,2,3]) console.log(i)
for await (let i of [1,2,3]) console.log(i)
    ^^^^^

SyntaxError: Unexpected reserved word

This works:

> (async () => { for await(let i of [1,2,3]) console.log(i) })()
Promise {
  <pending>,
  domain: ...etc }
> 1
2
3

сс @nodejs/repl

This is expected, await can be used only within async functions. Even from the link that you had shared, its says the following (below the code sample):

Async for-of statements are only allowed within async functions and async generator functions (see below for the latter).

That's the exact reason why it works perfectly fine, when you wrap with async.

Edit: Looks like repl supports top level `await`.

its would seem to be a bug in https://github.com/nodejs/node/blob/master/lib/internal/repl/await.js

So the visitors don't check for a ForOfStatement with await: true, which means state.containsAwait ends up being false, and its not handled.

fix looks like this nodejs/repl@2003bc5 if anyone wants to take it

@devsnek

@devsnek happy to handle this!

Oh snap! Thank you so much for addressing this so quickly! 🤩

repl: support top-level for-await-of

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`for await of` syntax doesn't work with --experimental-repl-await #23836

Edit: Looks like repl supports top level `await`.

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for await of syntax doesn't work with --experimental-repl-await #23836

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vsemozhetbyt commented on Oct 23, 2018

antsmartian commented on Oct 24, 2018

Edit: Looks like repl supports top level await.

devsnek commented on Oct 24, 2018

devsnek commented on Oct 24, 2018

codebytere commented on Oct 24, 2018

RangerMauve commented on Oct 24, 2018

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`for await of` syntax doesn't work with --experimental-repl-await #23836

Edit: Looks like repl supports top level `await`.