http://blog.nodejs.org/2011/03/23/npm-1-0-global-vs-local-installation
https://docs.npmjs.com/files/folders
tl;dr
Install it locally if you're going to require() it.
Install it globally if you're going to run it on the command line.
http://blog.nodejs.org/2011/03/23/npm-1-0-global-vs-local-installation
https://docs.npmjs.com/files/folders
tl;dr
Install it locally if you're going to require() it.
Install it globally if you're going to run it on the command line.