any (escape hatch), unknown (safe top type), never (no values)
bigint, symbol
Examples
let s: string = "hello";
let n: number = 42;
let ok: boolean = true;
let id: symbol = Symbol("id");
let large: bigint = 9007199254740991n;
function log(msg: string): void { console.log(msg); }
let anything: any = 123; // avoid in real code when possible
let top: unknown = JSON.parse("{}");
function fail(message: string): never { throw new Error(message); }
Literal and widening
const color = "red"; // type is "red" (literal)
let mutableColor = "red"; // type is string (widened)