ReactiveX is based on two entities: observables and observers. These are the only things that one needs to understand to be able to start writing code. Everything else is based on the behavior of one of these two entities.
Observables represent a source of events. An observable is an entity that can emit zero or one of several items. An observable has an explicit lifetime with a start and an end. When an observable completes or faces an error, it cannot send items anymore; its lifetime has ended. An observable may never end. In this case, it is an infinite source of events. Observables are a way to manage sequences of items in an asynchronous way. Table 1.1, which follows, shows a comparison between how to access items ...
