经典的发布订阅者模式

function Pubsub() {    this.handlers = {};}Pubsub.prototype = {    on: function (eventType, handler) {        var self = this;        if (!(eventType in self.handlers)) {            self.handlers[eventType] = [];        }        self.handlers[eventType].push(handler)    },    emit: function (eventType) {        var self = this;        var handlerArgs = Array.prototype.slice.call(arguments, 1);        for (var i = 0; i < self.handlers[eventType].length; i++) {            self.handlers[eventType][i].apply(self, handlerArgs)        }        return self;    },    off: function (eventType, handler) {        var currentEvent = this.handlers[eventType];        var len = 0;        if (currentEvent) {            len = currentEvent.length;            for (var i = len - 1; i >= 0; i--) {                if (currentEvent[i] === handler) {                    currentEvent.splice(i, 1)                }            }        }        return this;    }}

var pubsub = new Pubsub();var callback = function (data) {    console.log(data)}pubsub.on(‘A‘, function (data) {    console.log(data + 1)})pubsub.on(‘A‘, function (data) {    console.log(data + 2)})pubsub.on(‘A‘, callback)pubsub.emit(‘A‘, ‘参数‘)pubsub.off(‘A‘, callback)pubsub.emit(‘A‘, ‘二参数‘)

原文地址：https://www.cnblogs.com/liuhao-web/p/8302845.html