TypeScript的super

(function(){
class Animal{
  name:string;

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

  sayHello(){

    console.log('动物再叫---');

  }

}
class Dog extends Animal {
  age:number;
  constructor(name:string,age:number){
    super(name);
    this.age=age;
  }
    sayHello() {
      // super.sayHello();

      console.log('汪汪汪！');

    }
}
const dog=new Dog('旺财',18);
dog.sayHello();
})();