Automating nested namespacing. Credited to Addy Osmani, based on a pattern by Stoyan Stefanov. http://goo.gl/T8Vqk

ExtendNamespace

// Convenience function for parsing string namespaces and 
// automatically generating nested namespaces
function extendNamespace( ns, ns_string ) {
  var parts = ns_string.split("."),
  	parent = ns,
		pl;

	pl = parts.length;

	for ( var i = 0; i < pl; i++ ) {
		// create a property if it doesn't exist
		if ( typeof parent[parts[i]] === "undefined" ) {
			parent[parts[i]] = {};
		}

		parent = parent[parts[i]];
	}

	return parent;
}

// usage 
var MY_APP = MY_APP || {};

var singleLevelNestedNamepace = extendNamespace(MY_APP, "descendant1");
console.log(singleLevelNestedNamepace == MY_APP.descendant1);  // outputs true

var doubleLevelNestedNamepace = extendNamespace(MY_APP, "descendant1.descendant2");
console.log(doubleLevelNestedNamepace == MY_APP.descendant1.descendant2);  // outputs true