打字稿可扩展任何类型

Question

这是装饰器函数：

const func = className => {
  let instance = new className();
  extendObservable(instance, instance.observables);
  return instance;
};

export default func;

这是课程：

@func
class testClass {
  observables = {
    name: "",
    fname: "",
    age: 0,
  };
  .
  .
  .
  .
  someMethod() {
    let a = this.name  // <<<<< I'm getting property name does
                       //       not exist on type testClass
  }
}

如何在不将所有可观察对象的属性复制到此类的情况下消除此错误：

 name: string
 fname: string
 age: number
 observables = {
    name: "",
    fname: "",
    age: 0,
  };