手写发布订阅

// 创建一个发布者类
class Publisher {
  constructor() {
    this.observers = [];
    console.log("init");
  }
  // 增加订阅者
  add(observer) {
    console.log("add");
    this.observers.push(observer);
  }
  // 移除订阅者
  remove(observer) {
    console.log("remove");
    this.observers.forEach((item, index) => {
      if (item === observer) {
        this.observers.splice();
      }
    });
  }
  // 通知所有订阅者
  notify() {
    console.log("notify");
    this.observers.forEach((observer) => {
      observer.update(this);
    });
  }
}
// 创建一个订阅者类
class Observer {
  constructor() {
    console.log("observer");
  }
  update() {
    console.log("update");
  }
}
class PrdPublisher extends Publisher {
  constructor() {
    super();
    this.prdState = null;
    this.observers = [];
    console.log("PrdPublisher init");
  }
  // 该方法用于获取当前的prdState
  getState() {
    console.log("getState");
    return this.prdState;
  }
  // 改变prdState的状态
  setState(state) {
    console.log("set");
    this.prdState = state;
    this.notify();
  }
}
class DeveloperObserver extends Observer {
  constructor() {
    super();
    this.prdState = {};
    console.log("developer init");
  }
  // 重写一个update的方法
  update(publisher) {
    console.log("new update");
    // 更新需求文档
    this.prdState = publisher.getState();
    // 开始工作
    this.work();
  }
  // work 开始搬砖
  work() {
    const prd = this.prdState;
    console.log("996 begins...", prd);
  }
}
const pika = new DeveloperObserver()
const A = new DeveloperObserver()
const B = new DeveloperObserver()
const xx = new PrdPublisher()
const prd = {
    name: '1231'
}
xx.add(pika)
xx.add(A)
xx.add(B)
xx.setState(prd)