Javascript设计模式-发布/订阅模式最小化的示例

示例代码

/*经典的发布/订阅模式*/var pubs = {};(function(p){    var events = {},        subId = -1;    var subscribe = p.subscribe = function(name, callback, one){        var list = events[name] || (events[name] = []),            token = (++subId).toString();        list.push({            'token' : token,            'callback' : callback         });        return token;    }   var publish = p.publish = function(name, data){        var list = events[name], func;        if(list){            // Copy callback lists to prevent modification            list = list.slice()            // Execute event callbacks            while((func = list.shift()) && func.callback){                func.callback(name, data);            }        }     }    // Remove event. If `callback` is undefined, remove all callbacks for the    // event. If `event` and `callback` are both undefined, remove all callbacks    // for all events   var unsubscribe = p.unsubscribe = function(name, callback){        if (!(name || callback)) {            events = {};            return p;        }        var list = events[name];        if(list){            if(callback){                for (var i = list.length - 1; i >= 0; i--) {                    if (list[i] === callback) {                      list.splice(i, 1);                    }                }            }else{                delete events[name];            }        }    }})(pubs);

调用代码

     var messageLogger = function(name, data){                console.log(new Date().getTime() + "--Loggin : " + name + ":" + data )            };            var subcription = pubs.subscribe('inbox/newMessage', messageLogger);            pubs.publish('inbox/newMessage', 'Hello World');            pubs.publish('inbox/newMessage', 'Hello, are you still there?');            pubs.unsubscribe('inbox/newMessage');

这个模式多被用在各个框架的事件模型中，其中Backbone中使用的比较典型。