TypeScript Cheatsheet

Primitives

string, number, boolean

Array, Array<string>, Array<number>, Array<any>
string[], number[], any[]

obj: { firstname: string, lastname: string }

const sayHi = (prefix: string): string => `${prefix} Hello`

interface Person {
  gender: string;
}

interface User extends Person {
  id: number;
  firstname: string;
  age?: number;
}

type Point = {
  x: number;
  y: number;
};

type Door = "open" | "closed"
function print(text: string | string[]) {}