$ npm install -g json-schema-generator
...
npm http fetch GET http://npm-registry01.prd.nytimes.com/wordwrap/-/wordwrap-0.0.2.tgz
npm ERR! cb() never called!
either ditch their npm-shrinkwrap.json from the published package, or to make sure that it's not pointing to their private registry when they publish the package to the public registry
~ @othiym23 at https://github.com/npm/npm/issues/7146#issuecomment-70358849