观察者模式(Observer)

定义对象之间的一对多依赖关系，以便当一个对象更改状态时，将自动通知和更新其所有依赖项。

class User {
  constructor(name) {
    this.name = name;
  }
  sendPrice(target, price) {
    target.addPrice(price);
  }
  getPrice(target) {
    return target.getPrice();
  }
}

class Auction {
  constructor() {
    this.price = 0;
    this.sellState = true;
  }
  addPrice(price) {
    this.sellState ? (price > this.price ? (this.price = price) : "") : "";
  }
  getPrice() {
    return this.price;
  }
  closeSell() {
    this.sellState = false;
  }
}

export { User, Auction };

let user1 = new User("julong");
let user2 = new User("dao");
let auction = new Auction();
user1.sendPrice(auction, 12);
user2.sendPrice(auction, 32);
user1.getPrice(auction);
auction.closeSell();
user2.sendPrice(auction, 36);
user1.getPrice(auction);

#观察者模式(Observer)

观察者模式(Observer)