在typescript中,是否有任何方法可以将对象用作键?

我有两个班:

class A {
  name: string;
  age: number;

  constructor(name: string, age: number) { 
      this.name = name;
      this.age = age;
  }
}

class B extends A {

}

另外,我还有一个对象,我想在其中使用这些类的实例作为键:

const storage: Storage = {};

所以看起来是这样的:

const a = new A('Neo', 25);
const b = new A('Smith', 31);
storage[a] = 'What are you trying to tell me? That I can dodge bullets?';
storage[b] = 'Never send a human to do a machine's job.'

然后我想按键区分值,比如:

const keys = Object.keys(storage);
keys.forEach(key => {
  if (key instanceof A) {
    console.log('This is Neo');
  } else if (key instanceof B) {
    console.log('This is Smith');
  }
})

看起来怎么样 Storage 接口,因为在typescript中

索引签名参数类型必须是“string”或“number”