const message: string = "Hello, world!";
console.log(message);

Run with a TypeScript runtime or compile first:

npx tsx main.ts

This defines a typed string and logs it. It is the basic TypeScript shape for a tiny script.

type User = {
  id: number;
  name: string;
  active: boolean;
};

const user: User = {
  id: 1,
  name: "Dan",
  active: true,
};

This type describes the expected object shape, then the object literal follows that contract.

function greet(name: string): string {
  return `Hello, ${name}!`;
}

console.log(greet("world"));

This function makes both the input and output types explicit, which is one of the main benefits of TypeScript.