es6 - 箭头

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

     changeName(name) {
         this.name = name;
     }

     changeAge(age) {
         this.age = age;
     }

     chage(name, age) {

         // 本this -> 获取的是全局的this
         var self = this;
         let fn = () => {
 　　　　　　//无论嵌套多少层 -> 只要通过箭头符号获取的就是全局的
             (() => {
                 (() => {
                     (() => {
                         console.log('全局this：', self);
                         this.changeAge(age);
                         this.changeName(name);
                     })();
                 })()
             })()

             console.log('全局this：', self);
             this.changeAge(age);
             this.changeName(name);
         }

         // function fn() {
         //     // 当前 - 带箭头 -> 全局
         //     this.changeAge(age);
         //     this.changeName(name);
         // }

         fn();
     }

 }

 var user = new User('zhang', 30);
 user.chage('long', 20);

 console.log('chage修改后：', user);

 //  函数 -es5
 function calc(x, y) {
     return x * y;
 }

 console.log(calc(1, 5));

 //  函数 -es6
 var es6calc = (x, y) => {
     return x * y;
 }

 console.log(es6calc(1, 2));