Hands-On Reactive Programming with Python

ReactiveX Subject

A Subject is a kind of proxy or bridge that implements both an observable and an observer. Several variants of subjects exist in ReactiveX and in RxPY. The RxPY implementation of the Subject object corresponds to the PublishSubject in ReactiveX terminology. Its behavior is a follows: it emits—to an observer—the items of its source observable that are emitted after the observer subscribes to the Subject. This behavior is shown in the following figure:

Figure 3.3: The PublishSubject, or Subject, in RxPY

If the source observable of the subject was a cold observable, then it becomes a hot observable. This means that the items ...