Install NodejS application Globally

It's really easy to install a Node module from NPM with:

sudo npm install -g ModuleName

But how about doing the same from a Node application code that is on the same machine?
How can it be installed globally? I want to be able to execute it without entering the full path and without publishing it to NPM.

Thanks Chad, that's correct. I can just go inside the application and run sudo npm install -g.