Lesson 8 — Type aliases

Give a type a name

A type alias (type Name = …) gives a reusable name to any type: a union, an object shape, a function type. Instead of repeating string | number everywhere, you write ID once and use it, so changing it later is one edit.

type Point = { x: number; y: number };
type Status = "open" | "closed";
const s: Status = "open";

Why it matters: good type names make code read like a description of your data.