Extremely basic pubsub example (please don't use it)

pubsub.js

(function(global) {
    
    var subs = {},
        slice = Array.prototype.slice;
    
    global.pubsub = {
        sub: function(topic, fn, ctx) {
            var sub = subs[topic] || (subs[topic] = []);
            
            sub.push({
                fn: fn,
                ctx: ctx
            }); 
        },
        
        pub: function(topic) {
            var topicSubs = subs[topic] || [],
                 args = slice.call(arguments, 1);
            
            for (var i = 0; i < topicSubs.length; i++) {
                var sub = topicSubs[i];
                sub.fn.apply(sub.ctx, args);   
            }
        }
    };
    
})(window.lib = window.lib || {});