How to install a private NPM module without my own registry

Question

I've taken some code and put it in an NPM module, one I don't want to upload to the central registry. The question is, how do I install it from other projects?

The obvious way is probably to set up my own NPM registry, but according to the documentation, that involves a lot of hassle.

Can I just install an NPM module that sits on the local filesystem, or perhaps even from git?

npm install --from-git git@server:project