npm install miniee

var MiniEE = require('miniee');
var MyClass = function() {};
MiniEE.mixin(MyClass);

var obj = new MyClass();    
// set string callback
obj.on('event', function(arg1, arg2) { console.log(arg1, arg2); });
obj.emit('event', 'aaa', 'bbb'); // trigger callback

// set regexp callback
obj.on(/event.*/, function(arg) { console.log(arg); });
// trigger regexp callback
obj.emit('event-123', 'aaa', 'bbb');

http://nodejs.org/api/events.html