ES6 Class类（简单理解封装和继承）

        class People{
            constructor({name}){
                this.name = name;
            }
            say(){
                return "hello";
            }
        }

        const people = new People({name:"tom"});
        console.log(people);   // People {name:"tom"}
        console.log(people.say())  //hello

        //继承
        class Jack extends People{   //Jack 继承于 People
            constructor(options){
                super(options)   //调用super方法之前 要给类继承父级
                this.age = options.age;
            }
        }

        const jack = new Jack({age:18,name:"jack"})
        console.log(jack)   //Jack {age:18,name:"jack"}
        console.log(jack.say())  //hello