ES6 Class的get、set使用

class Person {
            constructor(name, age) {
                this.name = name
                this.age = age
            }

            //__age__ = 0

            get age() {
                console.log("get is called")

                //return this.__age__
                return this.__proto__.__age__
            }
            set age(value) {
                console.log("set is called")

                if (value < 0) {
                    //this.__age__ = value * -1
                    this.__proto__.__age__ = value * -1
                } else {
                    //this.__age__ = value
                    this.__proto__.__age__ = value
                }
            }
        }
        Person.prototype.__age__ = 0
        let p1 = new Person("tom", -18)
        p1.age=19
        console.log(p1.age, p1)