Functional Programming

ELI5 — The Vibe Check

Functional programming is like cooking with strict rules: no shared bowls, no side dishes contaminating each other, and every dish must be exactly reproducible from the recipe. Functions take ingredients in and produce output — they never secretly modify the pantry.

Real Talk

Functional Programming is a paradigm that treats computation as the evaluation of pure functions, avoiding shared mutable state and side effects. It emphasises immutability, first-class functions, and declarative style via tools like map, filter, and reduce.

Show Me The Code

const numbers = [1, 2, 3, 4, 5];

// FP style: no mutation, chained transforms
const result = numbers
  .filter(n => n % 2 === 0)
  .map(n => n * 2);
// [4, 8]

When You'll Hear This

"We adopted a functional programming style to make the data pipeline easier to test." / "Pure functions and no side effects — that's the FP way."