I was curious about making retro gaming sounds using Sonic Pi. A couple of months and a lot of Googling later, here's the original Mario Bros theme as it was heard on the NES console.
I'm (just about) old enough to remember rushing home from school to play this game at Philip Boucher's house, sitting cross-legged in front of the TV till my feet got pins and needles. Working out how to recreate it for Sonic Pi was a lot of fun!
(by @andrestaltz)
So you're curious in learning this new thing called (Functional) Reactive Programming (FRP).
Learning it is hard, even harder by the lack of good material. When I started, I tried looking for tutorials. I found only a handful of practical guides, but they just scratched the surface and never tackled the challenge of building the whole architecture around it. Library documentations often don't help when you're trying to understand some function. I mean, honestly, look at this:
Rx.Observable.prototype.flatMapLatest(selector, [thisArg])
Projects each element of an observable sequence into a new sequence of observable sequences by incorporating the element's index and then transforms an observable sequence of observable sequences into an observable sequence producing values only from the most recent observable sequence.