Small & Recursive Namespace function

namespace.js

function namespace (ns) {
  var parts = ns.split('.'),
      root = window || this;
  
  return (function walk (obj) {
    if (!root[obj]) { root[obj] = {}; }
    root = root[obj];
    if (parts.length) { walk(parts.shift()); } 
    return root;
  }(parts.shift()));
}

// Example
namespace('MyApp.Controllers.Menu').Sidebar = (function () {
   // Code
}());