- Rx.js is the Microsoft one, which I use myself. See rxjs.dev/. It is well documented, unlike its competitors, but often seems over-engineered.
- highland was popular for a while but seems to be a little less frenetically active
- kefir also tries to be minimal. See home page
- of course there are more, why not bacon.js?
- task.js seems to be a coroutine-like hack for JS generators, by Mozilla
- Node.js has (maybe?) a front-runner co-routine implementation, node-fibers which might be ok
Fantasy land is a specification for algegraic strucures in Javascipt which happens to provide interoperation between the below libraries
The incredibly-similar-and-similarly-named transducers-js also works.