Opened a discussion here: https://groups.google.com/a/cloudfoundry.org/forum/#!topic/vcap-dev/QXbHOuNXAt8

Currently, when installing the dependencies for a user's Node app, we run this command:
npm install --userconfig $build_dir/.npmrc --production 2>&1 | indent

Seems that it would be valuable to give users the option to disable the "--production" flag so that their "devDependencies" in package.json can be installed. One use case is for developers who want their grunt dependencies installed on production, but it's a hassle because those dependencies are generally under "devDependencies".

Heroku's Node.js bulidpack supports this functionality via NPM_CONFIG_PRODUCTION

I'd be happy to open a PR should we decide to include this support!