1.ts中不支持继承多个类, 但是类可以作为接口来实现

// Person 类
class Person {
  name: string;
  sayHello() {
    console.log("tag", `Helo ${this.name}!`);
  }
}
// Student 类
class Student {
  grade: number;
  study() {
    console.log("tag", " I need Study!");
  }
}
class SmartObject implements Person, Student {
  // Person
  name: string = "person";
  sayHello: () => void;
  // Activatable
  grade: number = 3;
  study: () => void;
}

2.接口可以实现多继承

// 阿里接口
interface Ali {
  pay: () => void;
}
// 腾讯接口
interface Tencent {
  game: string;
  play: () => void;
}
// 自己的接口
interface Self extends Ali, Tencent 
// 这样谁implement Self的话就必须同事实现Ali和Tencent和Self定义的所有属性和方法