Part 2. Get functional

Part 1 answered the two most fundamental questions about this book: Why Functional? And why JavaScript? Now that you understand what functional programming brings to JavaScript development, I’ll take it up a few notches. In part 2, I’ll build on and discuss all the practical concepts and techniques you need in order to apply functional programming to solve real-world problems. In this part, you’ll learn what it means to “get functional.”

Chapter 3 takes a first look at some comprehensive functional programs by using declarative abstractions such as map, reduce, and filter, with the goal of creating code that’s easy to reason about. It also covers the use of recursion as a means of iterating through different forms of data in a functional style.

Chapter 4 takes the concepts from chapter 3 and applies them to constructing function pipelines to streamline development and write in a point-free style. You’ll learn that the key to building functional code is breaking up complex tasks into small, independent components that can be glued back together to form whole solutions via the principle of compositionality. The result is a modular and reusable code base.