将枚举传递给打字稿中的泛型类

Question

I want to create a generic typescript type which takes an enum and then verifies that keys in the type belong to that enum. I am looking for something like this:

enum Cars {
  Toyota = 'toyota',
  Lada = 'lada',
}

enum Planes {
  Boeing = 'boeing',
  Airbus = 'airbus',
}

type ImageList<T> = {
  // `key in Planes` works, but `key in T` doesn't
  [key in T]: string;
}

// And that's how I will use the type:
const images: ImageList<Planes> = {
  [Planes.Boeing]: 'https://...jpg',
  [Planes.Airbus]: 'https://...jpg',
};

The [key in T] syntax is invalid, although [key in Planes] works fine.

Answer 1

To do that, I did a union of the enums with the extends keyword:

type ImageList<T extends Cars | Planes> = {
  [key in T]: string;
}