This tutorial explains what is different and special about a functional programmer's approach, and demonstrates how to implement JavaScript functions from a functional programming point of view. It ...

Functional programming with arrays Although JavaScript’s arrays are very capable out of the box, the functional paradigm improves the clarity and maintainability of array code.

It’s a programming style that rose to prominence with languages like Clojure, Scala, and Elm, but you can get into the functional mindset right within JavaScript.