This reminds me Cycle.js. I would definitely think stream paradigm is very useful to front-end.

The essential difference in front-end, is the programmer is dealing with continous, realtime signals, and transform it into the graphical interface. This is very different from most request/response style back-end. And the stream is obviously a proper abstraction for modeling this.

However, I found it's tedious to work with RxJS or other stream libraries, not because the design itself, it's just JavaScript lack of flexible DSL machanism like macro. If you invent a DSL for a stream flow diagram, you can get a lot of very neat equations between source and sink, but for JavaScript it's very hard to abstract away the stream context syntactically.