ASE is your power house for all things Functional Reactive. If you've never heard of Functional Reactive Programming I highly suggest you check out RxJS. You can also check out RxNevermore. ASE takes heavy inspiration from the both of these.
If you've ever heard of either Functional Programming or Reactive Programming than you're already half way there. FRP is basically these two paradigms mashed together. We combine the immutability and lack of side effects from Functional then the reactive nature from Reactive. State is transformed through a series of operations and then you react to the final state.
Learning FRP is hard but the payoff is amazing. The easiest way to think about this is by thinking of water pipes. The water starts at one end and then throughout the piping system it changes, maybe you dial back the flow or maybe you change the direction of the water. Once the water reaches the end of the pipe its then caught and you react to this final state of the water.