node.js如何自定义实现一个EventEmitter

const EventEmitter = require('events')
class MyEmitter extends EventEmitter {}
const myEmitter = new MyEmitter()
function callback() {
    console.log('触发了event事件！')
}
myEmitter.on('event', callback)
myEmitter.emit('event')
myEmitter.removeListener('event', callback);

//事件派发机制
(function() {
    var EventDispatcher = function() {
        var EventDispatcherClosure = function() {

        };
        EventDispatcherClosure.prototype = {
            
            on: function(key, fn) {
                //获取当前的事件对象
                var curEvents = this._getCurEvents(key);
                //先检查该事件是否已经注册过了
                var flag = false;
                for (var i = 0, len = curEvents.length; i < len; i++) {
                    if (curEvents[i].name == fn.name) {
                        //已经出现过了,以最新注册的函数为主
                        flag = true;
                        curEvents[i] = fn;
                        break;
                    }
                }
                if (!flag) {
                    curEvents[curEvents.length] = fn;
                }
                this._reGISter(key, curEvents);
            },
            
            dispatch: function(key) {
                //获取当前的事件对象
                var curEvents = this._getCurEvents(key);
                var shouldDispatch = true;
                for (var i = 0, len = curEvents.length; shouldDispatch && i < len; i++) {
                    try {
                        //获取参数
                        var args = [];
                        for (var j = 1, len1 = arguments.length; j < len1; j++) {
                            args.push(arguments[j]);
                        }
                        shouldDispatch = curEvents[i].apply({}, args);
                    } catch (e) {
                        shouldDispatch = false;
                    }
                }
                return shouldDispatch;
            },
            remove: function(key) {
                if (this._getCurEvents(key)) {
                    delete EventDispatcherClosure.events[key];
                }
            },
            
            _getCurEvents: function(key) {
                return EventDispatcherClosure.events[key] || [];
            },
            
            _register: function(key, events) {
                EventDispatcherClosure.events[key] = events;
            },
        };
        EventDispatcherClosure.events = {};
        return {
            create: function() {
                return new EventDispatcherClosure();
            }
        };
    };
    window.EventDispatcher = new EventDispatcher().create();
})();

EventDispatcher.dispatch("test", obj)

EventDispatcher.on("test", function callback(obj) {
})

EventDispatcher.on("test")