[dns_snek]

> Obviously you can add modules calling to C/C++ functionality to a scripting language runtime easily

Yes, obviously, that's what NodeJS does. But you can't "just use the V8 runtime as-is if you're doing async IO", it doesn't have those facilities at all.

Async IO wasn't just "sold as an advantage", it is an advantage. Websockets were gaining popularity around that time and async IO is a natural fit for that.

You would have to change the language and boil the ocean to make the runtime support multiple threads (properly).

But why? Just to end up with the inferior thread-per-request runtime (which by the way, still needs to support async because it's part of the language), that requires developers to write JS which is incompatible with browser JS, which would've eliminated most of the synergy between the two?

I really don't understand what you're going for here. I don't see a single advantage here.

[luke5441]

I think green threads (Java Virtual Threads, Go to an extent) are strictly superior to async/await.

If you don't have many threads, OS threads are okay as well. It is all about memory and scheduling overhead.

But that is just my opinion. You are welcome to have a different opinion.

[dns_snek]

No I don't think your opinion is "wrong" or anything, it's just that this is a language-level limitation and not a valid criticism of NodeJS.