We have already learned that RxCpp operators operate on Observables (received as input) and return Observables. This allows these operators to be invoked one after the other using operator chaining. Each individual operator in the chain transforms elements in the stream received from the previous operator. The source stream is not mutated in the process. We use the fluent interface syntax when chaining operators.
Developers usually use the fluent interface in the context of the consumption of classes that implement the GOF Builder pattern. Builder pattern implementations are implemented in an order-independent manner. Even though the syntax of operator chaining is similar, the order in which operators are invoked does matter in the reactive world.
Let's write a simple program that will help us understand the significance of the order of execution in Observable operator chaining. In this particular example, we have an Observable stream where we apply the map operator...