1 ;(function(global ,undefined){ 2     var evts = {} 3         ,onceTag = ‘__event_once‘ 4     function emit(event ){ 5         var args = util.toArray(arguments , 1) 6         if (!(event in evts)) return 7         var _dels = [] 8         for (var i = 0 , j = evts[event].length ; i < j ;i ++){ 9             var cbk = evts[event][i]10             if (!cbk) return11             cbk.apply(null , args)12             if (cbk[onceTag])  { evts[event][i] = null ; _dels.push[i]}13         }14         for (var i = _dels.length -1 ; i>=0 ; i--) evts[event].splice(_dels[i] , 1)15     }16 17     function addMultiCon(event , listener){18         var once = true19         event.sort()20         addListener(event.join(‘|‘) , listener , once)21         var eventBubbles = []22         function tinOpener(evt){23             eventBubbles.push(evt)24             if (eventBubbles.length >=  event.length) {25                 eventBubbles.sort()26                 emit(eventBubbles.join(‘|‘))27             }28         }29 30         for (var i = 0 ; i < event.length;i ++){31             addListener(event[i] , tinOpener.bind(null, event[i]) , once)32         }33     }34 35     function addListener(event , listener , once){36         if (util.isArray(event)) return addMultiCon(event , listener)37 38 39         if (!(event in evts)) evts[event] = []40         if (once) listener[onceTag] = true41         evts[event].push(listener)42     }43 44     function removeListener(event, listener){45         if (!listener) {46             delete evts[event]47             return48         }49         for (var i = 0 , j = evts[event].length ; i < j ;i ++){50             if (evts[event][i] === listener) {  evts[event].splice(i, 1) ; break}51         }52     }53 54     function listeners(event){55         return evts[event]56     }57     global.emitter = {58         on : addListener59         ,once : function(event , listener){60                 addListener(event , listener , true)61                 }62         ,emit : emit63         ,listeners : listeners64     }65 })(this)

 function toArray(colletions ,offset){    return Array.prototype.slice.call(colletions , offset || 0)}