This detailed tutorial shows how to implement pure functions in JavaScript that are deterministic and referentially transparent, and create no side effects.

If you write JavaScript, you have probably used higher-order functions and not even noticed. If you have ever replaced a for loop with an array method, you’ve used higher-order functions.

JavaScript is a flexible language, allowing for all sorts of styles and programming paradigms. Although this breadth sometimes comes at a cost to readability or consistency across a code base, it ...