JavaScript设计模式之观察者模式与发布订阅模式详

// 观察者队列
class ObserverList{
  constructor(){
    this.observerList = {};
  }
  Add(obj,type = "any"){
    if(!this.observerList[type]){
      this.observerList[type] = [];
    }
    this.observerList[type].push(obj);
  }
  Count(type = "any"){
    return this.observerList[type].length;
  }
  Get(index,type = "any"){
    let len = this.observerList[type].length;
    if(index > -1 && index < len){
      return this.observerList[type][index]
    }
  }
  IndexOf(obj,startIndex,type = "any"){
    let i = startIndex,
      pointer = -1;
    let len = this.observerList[type].length;
    while(i < len){
      if(this.observerList[type][i] === obj){
        pointer = i;
      }
      i++;
    }
    return pointer;
  }
  RemoveIndexAt(index,type = "any"){
    let len = this.observerList[type].length;
    if(index === 0){
      this.observerList[type].shift();
    }
    else if(index === len-1){
      this.observerList[type].pop();
    }
    else{
      this.observerList[type].splice(index,1);
    }
  }
}
// 老板
class Boos {
  constructor(){
    this.observers = new ObserverList();
  }
  AddObserverList(observer,type){
    this.observers.Add(observer,type);
  }
  RemoveObserver(oberver,type){
    let i = this.observers.IndexOf(oberver,0,type);
    (i != -1) && this.observers.RemoveIndexAt(i,type);
  }
  Notify(type){
    let oberverCont = this.observers.Count(type);
    for(let i=0;i<oberverCont;i++){
      let emp = this.observers.Get(i,type);
      emp && emp(type);
    }
  }
}
class Employees {
 constructor(name){
  this.name = name;
 }
 getName(){
  return this.name;
 }
}
class Work {
 married(name){
  console.log(`${name}上班`);
 }
 unemployment(name){
  console.log(`${name}出差`);
 }
 writing(name){
  console.log(`${name}写作`);
 }
 writeCode(name){
  console.log(`${name}打代码`);
 }
}
let MyBoos = new Boos();
let work = new Work();
let aaron = new Employees("Aaron");
let angie = new Employees("Angie");
let aaronName = aaron.getName();
let angieName = angie.getName();
MyBoos.AddObserverList(work.married,aaronName);
MyBoos.AddObserverList(work.writeCode,aaronName);
MyBoos.AddObserverList(work.writing,aaronName);
MyBoos.RemoveObserver(work.writing,aaronName);
MyBoos.Notify(aaronName);

MyBoos.AddObserverList(work.married,angieName);
MyBoos.AddObserverList(work.unemployment,angieName);
MyBoos.Notify(angieName);
// Aaron上班
// Aaron打代码
// Angie上班
// Angie出差

class Utils {
 constructor(){
  this.observerList = {};
 }
 Add(obj,type = "any"){
  if(!this.observerList[type]){
   this.observerList[type] = [];
  }
  this.observerList[type].push(obj);
 }
 Count(type = "any"){
  return this.observerList[type].length;
 }
 Get(index,type = "any"){
  let len = this.observerList[type].length;
  if(index > -1 && index < len){
   return this.observerList[type][index]
  }
 }
 IndexOf(obj,startIndex,type = "any"){
  let i = startIndex,
    pointer = -1;
  let len = this.observerList[type].length;
  while(i < len){
   if(this.observerList[type][i] === obj){
    pointer = i;
   }
   i++;
  }
  return pointer;
 }
}
// 订阅者
class Subscribe extends Utils {};
// 发布者
class Publish extends Utils {};
// 中转站
class Broker {
 constructor(){
  this.publish = new Publish();
  this.subscribe = new Subscribe();
 }
 // 订阅
 Subscribe(fn,key){
  this.subscribe.Add(fn,key);
 }
 // 发布
 Release(fn,key){
  this.publish.Add(fn,key);
 }
 Run(key = "any"){
  let publishList = this.publish.observerList;
  let subscribeList = this.subscribe.observerList;
  if(!publishList[key] || !subscribeList[key]) throw "No subscribers or published messages";
  let pub = publishList[key];
  let sub = subscribeList[key];
  let arr = [...pub,...sub];
  while(arr.length){
   let item = arr.shift();
   item(key);
  }
 }
}
class Employees {
 constructor(name){
  this.name = name;
 }
 getName(){
  let {name} = this;
  return name;
 }
 receivedMessage(key,name){
  console.log(`${name}收到了${key}发来的消息`);
 }
}
class Public {
 constructor(name){
  this.name = name;
 }
 getName(){
  let {name} = this;
  return name;
 }
 sendMessage(key){
  console.log(`${key}发送了一条消息`);
 }
}
let broker = new Broker();
let SundayPublic = new Public("Sunday");
let MayPublic = new Public("May");
let Angie = new Employees("Angie");
let Aaron = new Employees("Aaron");
broker.Subscribe(() => {
 Angie.receivedMessage(SundayPublic.getName(),Angie.getName());
},SundayPublic.getName());
broker.Subscribe(() => {
 Angie.receivedMessage(SundayPublic.getName(),Aaron.getName());
},SundayPublic.getName());
broker.Subscribe(() => {
 Aaron.receivedMessage(MayPublic.getName(),Aaron.getName());
},MayPublic.getName());
broker.Release(MayPublic.sendMessage,MayPublic.getName());
broker.Release(SundayPublic.sendMessage,SundayPublic.getName());
broker.Run(SundayPublic.getName());
broker.Run(MayPublic.getName());
// Sunday发送了一条消息
// Angie收到了Sunday发来的消息
// Aaron收到了Sunday发来的消息
// May发送了一条消息
// Aaron收到了May发来的消息