Ah. I was coming at this from the perspective of "why would it be implemented this way in JavaScript specifically", as you'd asked about JS land. More generall

Ah. I was coming at this from the perspective of "why would it be implemented this way in JavaScript specifically", as you'd asked about JS land. More generally, I don't have a good enough overview of programming language trends to speak to how that fits in with other languages' approaches to async. > Is it common these days to mix promises and threads I'm not sure. That probably depends a lot on the evolutionary history of a given language and its library ecosystem. I could see it being done to mix those two things in a world where you are trying to glue together two libraries (or legacy internal modules) built in different ways, and the alternatives either don't exist or are more onerous.