To conclude this journey in functional and reactive programming, this last chapter contains some advice on how to use ReactiveX more efficiently, or avoid some issues. The first part helps you choose the operator adapted to each use case. The second part is a reminder of the reason why side-effects should contain as little code as possible. The third part indicates how to deal with situations where nothing happens. Finally, the last part contains recommendations, based on the way ReactiveX observables and observers are specified.

The following topics will be covered in this chapter:

• The observable creation decision tree
• Keep side-effects as small as possible
• What to do when nothing happens
• Miscellaneous recommendations