gistfile1.js

 var classesList = function(pref){
   var res = [];
   for (name in this) {
   if (this[name].xtype) {
     res.push(pref + name);
     this[name].classesList = classesList; // define the same function on each property on the fly
     res = res.concat(this[name].classesList(pref + name + ".")); // ... and call it, providing our name along with the scope
   }
 }