In this chapter, we've seen a common, simple problem, based on a real-life situation, and after analyzing several usual ways of solving that, we went for a functional thinking solution. We saw how to apply FP to our problem, and we also found a more general higher-order way that we could apply to similar problems, with no further code changes. We saw how to write unit tests for our code, to round out the development job. Finally, we even produced an even better solution (from the point of view of the user experience) and saw how to code it and how to unit test it.
In the next chapter 3, Starting Out with Functions - A Core Concept, we'll be delving more deeply into functions, which are at the core of all FP.