const volvoXC90 = {
  make: 'Volvo',
  model: 'XC90'
}
// typeof volvoXC90; returns the type { make: string; model: string }
// keyof typeof volvoXC90; return the literal type union { 'make' | 'model' }
type CarProps = keyof typeof volvoXC90;

let carProp: CarProps;

carProp = 'make';
carProp = 'model';
carProp = 'year'; // Error: Type '"year"' is not assignable to type '"make" | "model"'.(2322)