enum-type-refinement-example.ts

enum Make {
  Kia = 'Kia',
  Ford = 'Ford',
  Honda = 'Honda'
}

interface BaseCar {
  make: Make;
  color: string;
}

interface KiaCar extends BaseCar {
  make: Make.Kia;
  kiaSomethingSpecial: string;
}

interface FordCar extends BaseCar {
  make: Make.Ford;
  fordSomethingSpecial: string;
}

interface HondaCar extends BaseCar {
  make: Make.Honda;
  hondaSomethingSpecial: string;
}

type Car = KiaCar | FordCar | HondaCar;

function ensureUnreachable(value: never): never {
  throw "Reached unreachable code";
}

function drive(car: Car) {
  switch(car.make) {
    case Make.Kia:      
      console.log(car.kiaSomethingSpecial);
      break;
    case Make.Honda:
      break;
    case Make.Ford:
      break;
    default:
      ensureUnreachable(car);
  }
}