js设计模式中发布与订阅实现观察者模式例子

<script>
var pubsub = {};
(function(q) {
var topics = {};
subuid = -1;
q.publish = function(topic, args) {
if(!topics[topic]) {
return false;
}
var subs = topics[topic],
len = subs.length;
while(len--) {
subs[len].func(topic, args);
}
return this;
}
q.sub = function(topic, func) {
if(!topics[topic]) {
topics[topic] = [];
}
var token = ++subuid;
topics[topic].push({
token: token.toString(),
func: func
})
return token;
}
q.ubsub = 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);

</script>
<script id="test_data">
var topic = 'test/index';
pubsub.sub(topic, function() {alert(arguments[1])})
pubsub.publish(topic, 2)
pubsub.ubsub(0);
pubsub.publish(topic, 2)
</script>