(function () {
    class Animal {
        constructor(name) {
            this.name = name;
        }
    }
    /**
     * 若子类中想添加新的属性
     * 需要再构造函数中对父类的构造函数进行更新
     */
    class Cat extends Animal {
        constructor(name, age) {
            super(name);
            this.age = age;
        }
    }
    // class
    let c = new Cat('猫', 3);
    console.log(c);
})();