是否可以编写一个索引类型，其中键是区分联合的区分属性，值是联合成员

interface Dog {
  kind: 'dog';
  bark: () => void;
}

interface Cat {
  kind: 'cat';
  meow: () => void;
}

type Animal = Dog | Cat;

type AnimalByKind<K extends Animal['kind']> = Extract<Animal, { kind: K }>;

interface Dog {
  kind: 'dog';
  bark: () => void;
}

interface Cat {
  kind: 'cat';
  meow: () => void;
}

type Animal = Dog | Cat;

type AnimalByKind<K extends Animal['kind']> = Extract<Animal, { kind: K }>;

function makeSound(animal: Animal) {
  switch (animal.kind) {
    case 'dog':
      animal.bark();
      break;
    case 'cat':
      animal.meow();
      break;
  }
}

const myDog: Dog = { kind: 'dog', bark: () => console.log('Woof!') };
const myCat: Cat = { kind: 'cat', meow: () => console.log('Meow!') };

makeSound(myDog); // 输出: Woof!
makeSound(myCat); // 输出: Meow!