I've never liked the comparison of Flux to functional reactive programming. It's really just good ol' object-oriented design. Actions are akin to the Command pattern and the Dispatcher feels like a Mediator. Passing callbacks instead of objects and making a mostly directed graph does not yield FRP.

In my latest project, I used React with rx-react (https://github.com/fdecampredon/rx-react) and RxJS. That combination definitely made for some FRP fun.