Mastering JavaScript Functional Programming - Second Edition

A different way of thinking

FP is a different way of writing programs, and can sometimes be difficult to learn. In most languages, programming is done in an imperative fashion: a program is a sequence of statements, executed in a prescribed fashion, and the desired result is achieved by creating objects and manipulating them, which usually means modifying the objects themselves. FP is based on producing the desired result by evaluating expressions built out of functions that are composed together. In FP, it's common to pass functions around (such as passing parameters to other functions or returning functions as the result of a calculation), to not use loops (opting for recursion instead), and to skip side effects (such as modifying objects ...