JavaScript 观察者模式

Question

class Observer {
  update(data) {
    // 处理收到的通知数据
    console.log(`Received data: ${data}`);
  }
}

class Subject {
  constructor() {
    this.observers = [];
  }

  attach(observer) {
    this.observers.push(observer);
  }

  detach(observer) {
    const index = this.observers.indexOf(observer);
    if (index > -1) {
      this.observers.splice(index, 1);
    }
  }

  notify(data) {
    for (const observer of this.observers) {
      observer.update(data);
    }
  }
}