1 <script type="text/javascript">
2 //发布 emit 订阅 on {女生失恋:['哭','购物','吃']}
3 function Girl(){
4 this._events =
{}
5 }
6 Girl.prototype.on =
function(eventName,callback){
7 if(
this._events[eventName]){
//不是第一次
8 this._events[eventName].push(callback);
//{失恋:[cry,eat,shopping]}
9 }
else{
10 this._events[eventName] = [callback];
//{失恋:[cry]}
11 }
12 };
13 Girl.prototype.emit =
function(eventName,...args){
//用剩余运算符[我，你，他]，在参数里叫剩余运算符
14 //[].slice.call(arguments,1);都不理想
15 //Array.from(arguments).slice(1);
16 if(
this._events[eventName]){
17 this._events[eventName].forEach(cb=>cb(...args));
//在其他地方叫展开运算符
18 //this._events[eventName].forEach(cb=>cb.apply(this,args));
19 }
20 };
21 let girl =
new Girl();
22 let cry = (who)=>{console.log(who + '哭'
);};
23 let shopping = (who)=>{console.log(who + '购物'
);};
24 let eat = (who)=>{console.log(who + '吃'
);};
25 girl.on('失恋',cry);
//{失恋:[cry]}
26 girl.on('失恋',eat);
//{失恋:[cry,eat]}
27 girl.on('失恋',shopping);
//{失恋:[cry,eat,shopping]}
28
29 girl.emit('失恋','我'
);
30
31 //一对多
32 //{a:[fn,fn,fn]}
33 </script>
转载于:https://www.cnblogs.com/liufeiran/p/11162153.html
