Here is my problem. We have a private NPM registry which only works in VPN. I would like to have a fallback registry https://registry.npmjs.org so that when I am out of VPN
I use Strongloop's cli tools for that; see https://strongloop.com/strongblog/switch-between-configure-public-and-private-npm-registry/ for more information
Switching between repositories is as easy as : slc registry use