Add a stable module target for top-level await

[dtruffaut]

TypeScript Version:
3.9-beta

Search Terms:
top level await es2020 module

tsconfig.json
"target":"es2020"
"module":"es2020"

Code

await 1;

Expected behavior:

OK if "module":"esnext" in tsconfig.json
OK if "module":"es2020" in tsconfig.json

Actual behavior:

OK if "module":"esnext" in tsconfig.json
KO if "module":"es2020" in tsconfig.json <----- :'(

Top-level 'await' expressions are only allowed when the 'module' option is set to 'esnext' or 'system', and the 'target' option is set to 'es2017' or higher. ts(1378)

Playground Link:

"module":"es2020" is not available on Typescript playground.
"module":"es2020" is not available in documentation.

Related Issues:

#35813 - Add top-level await for esnext and system modules

Basically, just add "es2020" to the list.
Easy to fix, bro.

[RyanCavanaugh]

The ES2020 feature list has not been ratified yet, so we can't definitively say TLA will be part of it, but we're expecting that to happen at the upcoming TC39 meeting.

[DanielRosenwasser]

It definitely won't be in ES2020 - it isn't up for any new features, and top-level await is still stage 3.

[DanielRosenwasser]

I have misspoken slightly - Ryan is right, and that combined with the spec ratification timeline, means that some features that hit stage 4 at the current meeting might make it into ES2020 (e.g. import.meta). But top-level await isn't up for discussion at this meeting.

[mitar]

So, top-level await has been standardized. What this means for this issue?