Top level async

[michaelwclark]

Issue description or question

I'd love to see quokka handle async/await at top level. For quick prototyping this would be awesome!

Sample code

const test = async a => Promise.resolve(a)

console.log(test(4))
//Be awesome if we could.....
//console.log(await test(4)) 

//instead have to wrap async stuffs:
const getTest = async () => {
  const result = await test(4)
  console.log(result)
}

getTest().then()

Quokka.js Console Output

​​​​Quokka 'Untitled-3.js' (node: v10.5.0)​​​​

Promise {} ​​​​​at ​​​test(4)​​​ ​quokka.js:3:0​

4 ​​​​​at ​​​result​​​ ​quokka.js:10:2​

[smcenlly]

Thanks for the feature request. We'll need to do some investigation to see if there are any side effects, but agree this would be a nice feature.

[ArtemGovorov]

While not exactly the same as the originally requested feature, Quokka live comments (unlike console.log) support logging promise resolved values, so for your example you may do:

const test = async a => Promise.resolve(a)

test(4)//?

[ArtemGovorov]

The feature is implemented in the latest extension version.

[timarandras]

@ArtemGovorov While the simple top-level await is working, this is not:

async function* asyncGen() {
  yield Promise.resolve(1);
}

for await (const ret of asyncGen()) {
  console.log(ret);
}

Failed to instrument quokka.js 
  3 | } 
  4 |  
> 5 | for await (const ret of asyncGen()) { 
    |     ^ SyntaxError: Unexpected token (5:4) 
  6 |   console.log(ret); 
  7 | }

Wrapping in an async funciton works tough:

async function f() {
  for await (const ret of asyncGen()) {
    console.log(ret);
  }
}

f()

What can we do?

[smcenlly]

@timarandras - thanks for reporting your problem. We've updated our instrumentation code to handle this case. Please update to the latest version of Quokka for your editor to get this fix.

[timarandras]

Works! Thank you.

[thunderkid]

This top-level await feature seems to work only in js files, and not in typescript files, where I still get the old await is only allowed inside an async function error. Is that correct? Any plans to allow in typescript too?

[smcenlly]

Unfortunately we can't support top-level await for TypeScript until it is supported by the TypeScript compiler. You may subscribe to the TypeScript issue if you are interested in updates.

[SwiftWinds]

Top-level await was shipped in TypeScript 3.8. However, it still doesn't work in Quokka:

I'm using Webstorm 2021.2.3 w/ Quokka v1.0.317

[ArtemGovorov]

@SwiftWinds In order to make it work in Typescript, you need to configure your Quokka to use native ESM, so that your Quokka file runs as a module (as the error message suggests).