javascript get set读取器

    class Person{
    
        constructor(name, id){

            let _name = name, _id = id;
            
            Object.defineProperties(this, {
            
                name:{
                    //每次获取this.name的时候都会调用get方法
                    get:()=>{return _name;},
                    //每次修改this.name的时候都会调用set方法
                    set:(v)=>{_name = v; document.write(v);}
                },
                
                id:{
                    get:()=>{return _id;},
                    set:(v)=>{_id = v; document.write(v);}
                }
                
            });
            
        }
        
    }
    //test
    let p = new Person("w_1");
    console.log(p);
    p.name = "w_2";//w_2