Splitting a JavaScript namespace into multiple files

Let's say I have a namespace like that:

var myNamespace = {
    foo: function() {

    },
    bar: function() {
    }
};

What is the best way to split this code into files defining foo and bar separately?

I'm not worried about loading time - I'll concatenate it back into one file before deployment.

Answer

At the start of each file:

if(myNameSpace === undefined) {
  var myNameSpace = {};
}

File 1:

myNamespace.foo = function()...

File 2:

myNamespace.bar = function()...