lookup-types.ts

interface Person {
  name: string;
  age: number;
  location: string;
}

type P1 = Person["name"]; // string
type P2 = string[][0]; // string
type P3 = string[]["length"]; // number
type P4 = [string]["length"]; // 1
type P5 = [string, string]["length"]; // 2