In computing, reactive programming is a programming paradigm oriented around data flows and the propagation of change. This means that it should be possible to express static or dynamic data flows with ease in the programming languages used, and that the underlying execution model will automatically propagate changes through the data flow.
The tag reactive-programming was recently created for this question. The asker originally created the tags rxjs and socket.io for the question, but I removed them in an edit as I didn't think tags should be created without a good case. My edit prompted the asker to create reactive-programming instead. I don't know anything about this programming paradigm which is why I've come here to ask.
14 questions currently match reactive is:question
and are tagged with the names of various frameworks (system.reactive, react.js etc).
We have the tags oop (discussed recently here) and functional-programming. The reactive programming paradigm seems to be more "meta" as it can be applied in both object oriented and functional programming.