// 由于這些成員對(duì)于任何發(fā)布者對(duì)象都是通用的，故將它們作為獨(dú)立對(duì)象的一個(gè)部分來實(shí)現(xiàn)是很有意義的。那樣我們可將其復(fù)制到任何對(duì)象中，并將任意給定對(duì)象變成一個(gè)發(fā)布者。
// 如下實(shí)現(xiàn)一個(gè)通用發(fā)布者，定義發(fā)布者對(duì)象……
let publisher = {
 subscribers: {
  any: []
 },
 subscribe: function (fn, type = `any`) {
  if (typeof this.subscribers[type] === `undefined`) {
   this.subscribers[type] = [];
  }
  this.subscribers[type].push(fn);
 },
 unSubscribe: function (fn, type = `any`) {
  let newSubscribers = [];
  this.subscribers[type].forEach((item, i) => {
   if (item !== fn) {
    newSubscribers.push(fn);
   }
  });
  this.subscribers[type] = newSubscribers;
 },
 publish: function (args, type = `any`) {
  this.subscribers[type].forEach((item, i) => {
   item(args);
  });
 }
};
// 定義一個(gè)函數(shù)makePublisher()，它接受一個(gè)對(duì)象作為參數(shù)，通過把上述通用發(fā)布者的方法復(fù)制到該對(duì)象中，從而將其轉(zhuǎn)換為一個(gè)發(fā)布者
function makePublisher(obj) {
 for (let i in publisher) {
  if (publisher.hasOwnProperty(i) && typeof publisher[i] === `function`) {
   obj[i] = publisher[i];
  }
 }
 obj.subscribers = { any: [] };
}
// 實(shí)現(xiàn)paper對(duì)象
var paper = {
 daily: function () {
  this.publish(`big news today!`);
 },
 monthly: function () {
  this.publish(`interesting analysis`, `monthly`);
 }
};
// 將paper構(gòu)造成一個(gè)發(fā)布者
makePublisher(paper);
// 看看訂閱對(duì)象joe，該對(duì)象有兩個(gè)方法：
var joe = {
 drinkCoffee: function (paper) {
  console.log(`Just read ` + paper);
 },
 sundayPreNap: function (monthly) {
  console.log(`About to fall asleep reading this ` + monthly);
 }
};
// paper注冊(cè)joe（即joe向paper訂閱）
paper.subscribe(joe.drinkCoffee);
paper.subscribe(joe.sundayPreNap, `monthly`);
// 即joe為默認(rèn)“any”事件提供了一個(gè)可被調(diào)用的方法，而另一個(gè)可被調(diào)用的方法則用于當(dāng)“monthly”類型的事件發(fā)生時(shí)的情況?，F(xiàn)在讓我們來觸發(fā)一些事件：
paper.daily();   // Just read big news today
paper.daily();   // Just read big news today
paper.monthly();  // About to fall asleep reading this interesting analysis
paper.monthly();  // About to fall asleep reading this interesting analysis
paper.monthly();  // About to fall asleep reading this interesting analysis

// 由于這些成員對(duì)于任何發(fā)布者對(duì)象都是通用的，故將它們作為獨(dú)立對(duì)象的一個(gè)部分來實(shí)現(xiàn)是很有意義的。那樣我們可將其復(fù)制到任何對(duì)象中，并將任意給定對(duì)象變成一個(gè)發(fā)布者。
// 如下實(shí)現(xiàn)一個(gè)通用發(fā)布者，定義發(fā)布者對(duì)象……
class Publisher {
 constructor(){
  this.subscribers = {
   any: []
  }
 }
 subscribe(fn, type=`any`){
  if(typeof this.subscribers[type] === `undefined`){
   this.subscribers[type] = [];
  }
  this.subscribers[type].push(fn);
 }
 unSubscribe(fn, type=`any`){
  let newArr = [];
  this.subscribers[type].forEach((item, i) => {
   if(item !== fn){
    newArr.push(fn);
   }
  });
  this.subscribers[type] = newArr;
 }
 publish(args, type=`any`){
  this.subscribers[type].forEach((item, i) => {
   item(args);
  });
 }
 // 定義一個(gè)函數(shù)makePublisher()，它接受一個(gè)對(duì)象作為參數(shù)，通過把上述通用發(fā)布者的方法復(fù)制到該對(duì)象中，從而將其轉(zhuǎn)換為一個(gè)發(fā)布者
 static makePublisher(obj){
  obj.publisher = new Publisher();
 }
}
// 實(shí)現(xiàn)person對(duì)象
var person = {
 sayHi: function(name){
  this.publisher.publish(name);
 },
 sayAge: function(num){
  this.publisher.publish(num, `age`);
 }
}
// 將person構(gòu)造成一個(gè)發(fā)布者
Publisher.makePublisher(person);
// 看看訂閱對(duì)象myLover，該對(duì)象有兩個(gè)方法：
var myLover = {
 name: ``,
 hello: function(name){
  this.name = name;
  console.log(`Hi, i am ` + name + ` ! Nice to meet you!`);
 },
 timeOfLife: function(num){
  console.log(`Hello! My name is ` + this.name + ` ! I am ` + num + ` years old!`);
 }
}
// person注冊(cè)myLover（即myLover向person訂閱）
person.publisher.subscribe(myLover.hello);
person.publisher.subscribe(myLover.timeOfLife, `age`);
// 即myLover為默認(rèn)“any”事件提供了一個(gè)可被調(diào)用的方法，而另一個(gè)可被調(diào)用的方法則用于當(dāng)“age”類型的事件發(fā)生時(shí)的情況?，F(xiàn)在讓我們來觸發(fā)一些事件：
person.sayHi(`Jimmy`);  // Hi, i am Jimmy ! Nice to meet you!
person.sayAge(24);    // Hello! My name is Jimmy ! I am 24 years old!
person.sayHi(`Tom`);   // Hi, i am Tom ! Nice to meet you!
person.sayAge(6);     // Hello! My name is Tom ! I am 6 years old!
person.sayAge(18);    // Hello! My name is Tom ! I am 18 years old!