Event.js

/**
 * Event
 * var a = new Event()

 //添加监听 test事件
 a.on('test',function(msg){
  alert(msg)
})

 //触发 test事件
 a.fire('test','我是第一次触发')
 a.fire('test','我又触发了')

 a.off('test')

 a.fire('test','你应该看不到我了')
 * by kingpjchen 20160813
 */
define(function factory(require, exports, module) {


    var Class = require('./Class')

    //辅组函数，获取数组里某个元素的索引 index
    var _indexOf = function(array,key){
        if (array === null) return -1
        var i = 0, length = array.length
        for (; i < length; i++) if (array[i] === item) return i
        return -1
    }

    return Class.extend({
        //添加监听
        on:function(key,listener){
            //this.__events存储所有的处理函数
            if (!this.__events) {
                this.__events = {}
            }
            if (!this.__events[key]) {
                this.__events[key] = []
            }
            if (_indexOf(this.__events,listener) === -1 && typeof listener === 'function') {
                this.__events[key].push(listener)
            }

            return this
        },
        //触发一个事件，也就是通知
        fire:function(key){

            if (!this.__events || !this.__events[key]) return

            var args = Array.prototype.slice.call(arguments, 1) || []

            var listeners = this.__events[key]
            var i = 0
            var l = listeners.length

            for (i; i < l; i++) {
                listeners[i].apply(this,args)
            }

            return this
        },
        //取消监听
        off:function(key,listener){

            if (!key && !listener) {
                this.__events = {}
            }
            //不传监听函数，就去掉当前key下面的所有的监听函数
            if (key && !listener) {
                delete this.__events[key]
            }

            if (key && listener) {
                var listeners = this.__events[key]
                var index = _indexOf(listeners, listener)

                    (index > -1) && listeners.splice(index, 1)
            }

            return this;
        }
    })

})