Appendix A. The Algebra of Library Design
You might have noticed that all reactive abstractions we have encountered in this book have a few things in common. For one, they work as "container-like" abstractions:
- Futures encapsulate a computation that eventually yields a single value
- Observables encapsulate computations that can yield multiple values over time in the shape of a stream
- Channels encapsulate values pushed to them and can have them popped from it, working as a concurrent queue through which concurrent processes communicate
Then, once we have this "container," we can operate on it in a number of ways, which are very similar across the different abstractions and frameworks: we can filter the values contained in them, transform them using map, combine abstractions of the same type using bind/flatMap/selectMany, execute multiple computations in parallel, aggregate the results using sequence, and much more.
As such, even though the abstractions and their underlying...
