JavaScript allows us to program in a variety of different ways. Many of the examples we've shared so far in this book have been more inclined towards OOP, which primarily uses objects to express problem domains. Functional programming is different in that it uses mostly pure functions and immutable data to express problem domains.
All programming paradigms are broadly interested in the same thing: making it easier to express problem domains, to communicate our intent as programmers, and to accommodate the creation of useful and usable abstractions. The best principles we adopt from one paradigm may still apply to another, so adopt an open-minded approach!
It's easiest to observe and discuss the difference between OOP and functional programming by exploring an example. Let's imagine that we wish to build a mechanism so that we can...
