Learning Functional Programming in JavaScript

Supercharge Your Coding with Methods Map, Filter, Reduce and More

Photo by Fotis Fotopoulos on Unsplash

While JavaScript leans towards imperative and object-oriented, it has many useful functional programming concepts built right in that are worth learning.

Techniques like immutability, first-class functions, higher-order functions and recursion unlocks a whole new way to write code that is declarative, elegant and modular.

Let’s walk through the fundamentals of functional programming (FP) and how to leverage them in JavaScript.

What is Functional Programming?

Functional programming emphasizes writing software through pure functions — self-contained units that always return the same output given the same inputs. Code gets compartmentalized into small reusable pieces instead of changing states heavily.

Key principles include:

• Pure Functions
• Avoiding Shared State
• Immutability
• First-Class Functions
• Higher-Order Functions
• Recursion Over Loops

Mastering these concepts allows writing application logic as a series of data transformations via…