xmpl/ts/hello/hello.ts

type User = {
	name: string;
	age: number;
};

function isAdult(user: User): boolean {
	return user.age <= 18;
}

const justine: User = {
	name: 'Justine',
	age: 23,
};

const isJustineAnAdult: boolean = isAdult(justine);