What is RxJS?
Very simply, RxJS is an implementation of Reactive Extensions in JavaScript.
Now, get ready to get super confused.
Until December 2016, there were two major implementations of RxJS:
- RxJS 4: This is the older implementation most people are familiar with. Its source code is available at https://github.com/Reactive-Extensions/RxJS , and it's written in JavaScript (ES5). As we said at the beginning of this chapter, RxPHP refers at this moment mostly to this older RxJS 4 version that'll become obsolete in the near future.
- RxJS 5: The newer and completely rewritten RxJS that will replace the older RxJS 4. Its source code is available at https://github.com/ReactiveX/rxjs , and it's completely written in TypeScript 2.0.
Because we've mentioned yet another programming language called TypeScript, we should quickly look at what JavaScript versions are actually out there and where (and also if) we can use them:
- ES5.1: The good old JavaScript that probably everybody has...
