跟我学习javascript的最新标准ES6

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

//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...' 

//通过对象字面量创建对象var human = { breathe() { console.log('breathing...'); }};var worker = { __proto__: human, //设置此对象的原型为human,相当于继承human company: 'freelancer', work() { console.log('working...'); }};human.breathe();//输出 ‘breathing...'//调用继承来的breathe方法worker.breathe();//输出 ‘breathing...'

//产生一个随机数var num=Math.random();//将这个数字输出到consoleconsole.log(`your num is ${num}`);

var [x,y]=getVal(),//函数返回值的解构 [name,,age]=['wayou','male','secrect'];//数组解构function getVal() { return [ 1, 2 ];}console.log('x:'+x+', y:'+y);//输出：x:1, y:2 console.log('name:'+name+', age:'+age);//输出： name:wayou, age:secrect 

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

//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 

var people=['Wayou','John','Sherlock'];//sayHello函数本来接收三个单独的参数人妖，人二和人三function sayHello(people1,people2,people3){ console.log(`Hello ${people1},${people2},${people3}`);}//但是我们将一个数组以拓展参数的形式传递，它能很好地映射到每个单独的参数sayHello(...people);//输出：Hello Wayou,John,Sherlock //而在以前，如果需要传递数组当参数，我们需要使用函数的apply方法sayHello.apply(null,people);//输出：Hello Wayou,John,Sherlock 

for (let i=0;i<2;i++)console.log(i);//输出: 0,1console.log(i);//输出：undefined,严格模式下会报错

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

// point.jsmodule "point" { export class Point { constructor (x, y) {  public x = x;  public y = y; } }} // myapp.js//声明引用的模块module point from "/point.js";//这里可以看出，尽管声明了引用的模块，还是可以通过指定需要的部分进行导入import Point from "point"; var origin = new Point(0, 0);console.log(origin);

// 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;

// Weak Mapsvar wm = new WeakMap();wm.set(s, { extra: 42 });wm.size === undefined// Weak Setsvar ws = new WeakSet();ws.add({ data: 42 });//因为添加到ws的这个临时对象没有其他变量引用它，所以ws不会保存它的值，也就是说这次添加其实没有意思

//定义被侦听的目标对象var engineer = { name: 'Joe Sixpack', salary: 50 };//定义处理程序var interceptor = { set: function (receiver, property, value) { console.log(property, 'is changed to', value); receiver[property] = value; }};//创建代理以进行侦听engineer = Proxy(engineer, interceptor);//做一些改动来触发代理engineer.salary = 60;//控制台输出：salary is changed to 60

(function() { // 创建symbol var key = Symbol("key"); function MyClass(privateData) { this[key] = privateData; } MyClass.prototype = { doStuff: function() { ... this[key] ... } };})();var c = new MyClass("hello")c["key"] === undefined//无法访问该属性，因为是私有的

Number.EPSILONNumber.isInteger(Infinity) // falseNumber.isNaN("NaN") // falseMath.acosh(3) // 1.762747174039086Math.hypot(3, 4) // 5Math.imul(Math.pow(2, 32) - 1, Math.pow(2, 32) - 2) // 2"abcde".contains("cd") // true"abc".repeat(3) // "abcabcabc"Array.from(document.querySelectorAll('*')) // Returns a real ArrayArray.of(1, 2, 3) // Similar to new Array(...), but without special one-arg behavior[0, 0, 0].fill(7, 1) // [0,7,7][1,2,3].findIndex(x => x == 2) // 1["a", "b", "c"].entries() // iterator [0, "a"], [1,"b"], [2,"c"]["a", "b", "c"].keys() // iterator 0, 1, 2["a", "b", "c"].values() // iterator "a", "b", "c"Object.assign(Point, { origin: new Point(0,0) })

//创建promisevar promise = new Promise(function(resolve, reject) { // 进行一些异步或耗时操作 if ( /*如果成功 */ ) { resolve("Stuff worked!"); } else { reject(Error("It broke")); }});//绑定处理程序promise.then(function(result) { //promise成功的话会执行这里 console.log(result); // "Stuff worked!"}, function(err) { //promise失败会执行这里 console.log(err); // Error: "It broke"});