The approach of using __dirname is the most reliable one. It will always give you correct directory. You do not have to worry about ../../ in Windows environment as path.join() will take care of that.
There is an alternative solution though. You can use process.cwd() which returns the current working directory of the process. That command works fine if you execute your Node.js application from the base application directory. However, if you execute your Node.js application from different directory, say, its parent directory (e.g., node yourapp\index.js) then the __dirname mechanism will work much better.