//node事件模块 function Event () {
        this.cacheEvent = {} } Event.prototype.on = function (type, handle) {
        if (!this.cacheEvent[type]){
            this.cacheEvent[type] = [handle]     } else {
            this.cacheEvent[type].push(handle)     } } Event.prototype.emmit = function () {
        const type = arguments[0]     const arg = Array.prototype.slice.call(arguments, 1)     if (this.cacheEvent[type]) {
            for(let i = 0; i < this.cacheEvent[type].length; i++){
                this.cacheEvent[type][i](...arg)             if (this.cacheEvent[type][i].flag){
                    this.cacheEvent[type].splice(i,1)             }         }      } } Event.prototype.remove = function  (type, handle) {
        this.cacheEvent[type] = this.cacheEvent[type].filter(item => {
            return item !== handle     }) } Event.prototype.empty = function (type) {
        this.cacheEvent[type] = [] } Event.prototype.once = function (type, handle) {
        handle.flag = true     if (!this.cacheEvent[type]){
            this.cacheEvent[type] = [handle]     } else {
            this.cacheEvent[type].push(handle)     } }