Coroutines as a foundation for state machines, effect types and resumable exceptions. https://adam.nels.onl/blog/maybe-everything-is-a-coroutine

I think this is a really good idea from what I understand I've toyed with js generators to attempt a limited version of this idea a few years ago https://github.com/marcellerusu/capable-js and was surprised by the power of expressing certain things this way.