Example javascript namespace declaration helper

gistfile1.js

// Replace App with your root namespace name. 
// 
// use like: 
//   App.declare('foo.bar.baz', function(){});
//   App.foo.bar.baz();
// or
//   App.declare('some.namespaceName', {foo : function(){}, bar:function(){}});
//   App.some.namespaceName.foo();

var App = {};

(function() {
  App.declare = function(ns, obj) {
    if (typeof obj != 'function')
      return $.extend(createNamespace(splitNamespace(ns)), obj);

    return declareFunctionInNamespace(ns, obj);
  };

  function splitNamespace(ns) {
    return ns.split('.');
  }

  function declareFunctionInNamespace(ns, obj) {
    var namePieces = splitNamespace(ns);
    var lastPiece = namePieces.pop();

    var parent = createNamespace(namePieces);
    if (parent[lastPiece])
      $.extend(obj, parent[lastPiece]);

    var toMix = {};
    toMix[lastPiece] = obj;

    return $.extend(parent, toMix)[lastPiece];
  }

  function createNamespace(namePieces) {
    var obj = App;
    $.each(namePieces, function (i, name) {
      if (!obj[name]) {
        obj[name] = {};
      }
      obj = obj[name];
    });
    return obj;
  }
})();