I guess I really am on a roll today. Since I have written a post about uninstalling local packages, it was only logical to write posts about uninstalling global packages.
This npm inc. video is about uninstalling local packages.
Uninstalling global packages (docs.npmjs.com)
How to modify System Integrity Protection in El Capitan: (In case you have software hindered by it) Glenn Fleishman,September 30, 2015, MacWorld
El Capitan’s System Integrity Protection will shift utilities’ functions: Glenn Fleishman, July 15, 2015, MacWorld