emitter 增强 多条件触发

 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) return
11             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 = true
19         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] = true
41         evts[event].push(listener)
42     }
43 
44     function removeListener(event, listener){
45         if (!listener) {
46             delete evts[event]
47             return
48         }
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 : addListener
59         ,once : function(event , listener){
60                 addListener(event , listener , true)
61                 }
62         ,emit : emit
63         ,listeners : listeners
64     }
65 })(this)

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