In what scope are module variables stored in node.js?

Unlike the browser, where variables are by default assigned to the global space (i.e. window), in Node variables are scoped to the module (the file) unless you explicitly assign them to module.exports.

In fact, when you run node myfile.js or require('somefile.js') the code in your file is wrapped as follow:

(function (exports, require, module, __filename, __dirname) {
     // your code is here
});