function 可以用 =>  代替

var array = [1, 2, 3];//传统写法array.forEach(function(v, i, a) {    console.log(v);});//ES6array.forEach(v = > console.log(v));

可以支持类calss

//类的定义class Animal {    //ES6中新型构造器    constructor(name) {        this.name = name;    }    //实例方法    sayName() {        console.log('My name is '+this.name);    }}//类的继承class Programmer extends Animal {    constructor(name) {        //直接调用父类构造器进行初始化        super(name);    }    program() {        console.log("I'm coding...");    }}//测试我们的类var animal=new Animal('dummy'),wayou=new Programmer('wayou');animal.sayName();//输出 ‘My name is dummy’wayou.sayName();//输出 ‘My name is wayou’wayou.program();//输出 ‘I'm coding...’

字符串模板

` `  代替' '或" "

var a = '123';alert(`${a}`);

默认参数

function sayHello(name){    //传统的指定默认参数的方式    var name=name||'dude';    console.log('Hello '+name);}//运用ES6的默认参数function sayHello2(name='dude'){    console.log(`Hello ${name}`);}sayHello();//输出：Hello dudesayHello('Wayou');//输出：Hello WayousayHello2();//输出：Hello dudesayHello2('Wayou');//输出：Hello Wayou

不定参数

//将所有参数相加的函数function add(...x){    return x.reduce((m,n)=>m+n);}//传递任意个数的参数console.log(add(1,2,3));//输出：6console.log(add(1,2,3,4,5));//输出：15

for of遍历

var someArray = [ "a", "b", "c" ]; for (v of someArray) {    console.log(v);//输出 a,b,c}

Map Set

// Setsvar s = new Set();s.add("hello").add("goodbye").add("hello");s.size === 2;s.has("hello") === true;// Mapsvar m = new Map();m.set("hello", 42);m.set(s, 34);m.get(s) == 34;