experiments about EventTarget and nodejs polyfill

try-event-target.js

const isBrowser = (function() {
  try { return !!window; } catch (_) { return false; }
})();

if (isBrowser) {
  window.global = window;
}

const Event = isBrowser ? class extends window.Event {
  constructor(type, payload) {
    super(type);
    this.payload = payload;
  }
} : class {
  constructor(type, payload) {
    this.type = type;
    this.payload = payload;
  }
};
const EventTarget = isBrowser ? window.EventTarget : class extends require('events') {
  addEventListener(type, handler) {
    return this.addListener(type, handler);
  }
  dispatchEvent(event) {
    return this.emit(event.type, event);
  }
  removeEventListener(type, handler) {
    return this.removeListener(type, handler);
  }
};

// https://developer.mozilla.org/en-US/docs/Web/API/EventTarget
// https://developer.mozilla.org/en-US/docs/Web/API/Event
// https://nodejs.org/api/events.html#events_class_eventemitter
console.group('test EventTarget');
const someEventTarget = new EventTarget();
someEventTarget.addEventListener('hello', console.log);
someEventTarget.dispatchEvent(new Event('hello', { a: 123 }));
someEventTarget.removeEventListener('hello', console.log);
someEventTarget.dispatchEvent(new Event('hello', { a: 123 }));
console.groupEnd();