发布订阅模式

[dongtianqi]

代码：

var pubsub = {};
 (function(myObject) {
 // Storage for topics that can be broadcast
 // or listened to
 var topics = {};
 // An topic identifier
 var subUid = -1;
 // Publish or broadcast events of interest
 // with a specific topic name and arguments
 // such as the data to pass along
 myObject.publish = function( topic, args ) {
     if ( !topics[topic] ) {
         return false;
     }
     var subscribers = topics[topic],
         len = subscribers ? subscribers.length : 0;
     while (len--) {
         subscribers[len].func( topic, args );
     }
     return this;
 };
 // Subscribe to events of interest
 // with a specific topic name and a
 // callback function, to be executed
 // when the topic/event is observed
 myObject.subscribe = function( topic, func ) {
     if (!topics[topic]) {
         topics[topic] = [];
     }
     var token = ( ++subUid ).toString();
     topics[topic].push({
         token: token,
         func: func
     });
     return token;
 };
 // Unsubscribe from a specific
 // topic, based on a tokenized reference
 // to the subscription
 myObject.unsubscribe = function( token ) {
     for ( var m in topics ) {
         if ( topics[m] ) {
             for ( var i = 0, j = topics[m].length; i < j; i++ ) {
                 if ( topics[m][i].token === token ) {
                     topics[m].splice( i, 1 );
                     return token;
                 }
             }
         }
     }
     return this;
 };
}( pubsub ));