//父类
    class Person {
        name
        gender

        constructor(name, gender) {
            this.name = name
            this.gender = gender
        }

        sleep() {
            return `${this.name} 休息中...`
        }
    }

    //子类
    class David extends Person {
        web

        constructor(name, gender, web) {
            super(name, gender) //调用父类构造函数

            this.web = web
        }

        eat() {
            return `${this.name} 正在吃饭...`
        }
    }

    let david = new David("邓瑞", "男", "dengruicode.com")

    console.log("david", david)
    console.log("web", david.web)
    console.log("eat", david.eat())
    
    console.log("gender", david.gender)
    console.log("sleep", david.sleep())