Skip to main content

观察者模式

观察者模式​

let watcher_ids = 0;
let dep_ids = 0;
// 观察者类
class Watcher {
  constructor() {
    this.id = watcher_ids++;
  }
  // 观察到变化后的处理
  update(ob) {
    console.log("观察者" + this.id + `-检测到被观察者${ob.id}的${ob.state}`);
  }
}

// 被观察者类
class Dep {
  constructor() {
    this.watchers = [];
    this.id = observed_ids++;
    this.state = "默认状态";
  }
  // 添加观察者
  addWatcher(watcher) {
    this.watchers.push(Watcher);
  }
  // 删除观察者
  removeWatcher(watcher) {
    this.watchers = this.watchers.filter((w) => w.id != watcher.id);
  }

  // 通知自己所有的观察者，ob可以为被观察者自身
  notify(ob) {
    this.watchers.forEach((watcher) => {
      watcher.update(ob);
    });
  }
}