Demo EventNotification

class Event {
  name = null;
  callbacks = [];

  constructor(name) {
    this.name = name;
  }

  registerCallback = (callback) => {
    this.callbacks.push(callback);
  };
}

class EventNotification {
  events = {};

  addEventListener = (eventName, callback) => {
    if (!this.events[eventName]) {
      this.events[eventName] = new Event(eventName);
    }
    this.events[eventName].registerCallback(callback);
  };

  dispatchEvent = (eventName, eventArgs) => {
    if (!this.events[eventName]) {
      return console.log("no event name: ", eventName);
    }
    console.log("dispatch event ", eventName);
    this.events[eventName].callbacks.forEach((callback) => callback(eventArgs));
  };

  removeAllEventListeners = () => {
    for (let item in this.events) {
      delete this.events[item];
    }
  };

  removeEventListener = (eventName, callback) => {
    if (!this.events[eventName]) return;
    const len = this.events[eventName].callbacks.length;
    for (let i = 0; i < len; i++) {
      if (this.events[eventName].callbacks[i] === callback) {
        this.events[eventName].callbacks.splice(i, 1);
      }
    }
  };
}

const eventNotification = new EventNotification();

const cb1 = () => console.log("update 1");
const cb2 = () => console.log("update 2");

eventNotification.addEventListener("updateTask", cb1);
eventNotification.addEventListener("updateTask", cb2);

// eventNotification.removeEventListener("updateTask", cb1);
// eventNotification.removeEventListener("updateTask", cb2);

// eventNotification.removeAllEventListeners();

// console.log(eventNotification.events);

setTimeout(() => {
  console.log("run");
  eventNotification.dispatchEvent("updateTask");

  eventNotification.removeEventListener("updateTask", cb1);
  eventNotification.removeEventListener("updateTask", cb2);

  eventNotification.dispatchEvent("updateTask");

  // eventNotification.removeAllEventListeners();
  // console.log(eventNotification.events);
}, 2000);