[parser] Expose somehing like `program.extra.async` to easily know if a module uses top-level await

[nicolo-ribaudo]

[parser] Expose somehing like `program.extra.async` to easily know if a module uses top-level await

[nicolo-ribaudo]

I'm hesitant to use extra to affect how transforms work, because any plugin could inject a new async generator function.

[liuxingbaoyu]

I thought about something similar the other day, and this can also be used to avoid some traversals of the entire AST, such as transform-async-generator-functions. This is another way besides the order of plugins.
Perhaps we can put them in extra.usedFeatures.

[liuxingbaoyu]

You are right! If we just want to avoid traversing Program, that works too. Because other plugins run after that.
Of course, I personally prefer to avoid it by plugin order.