Extraneous Package when Installed Locally

Question

I was trying to install phantomjs in order to make test Twitter Bootstrap. After I had installed it locally i.e. npm install phantomjs, it

Answer 1

1. phantomjs should be included in your local .json package(manually editing it or using --save command see TheHippo's answer). If it is installed somewhere and you don't need it use the prune command

   npm prune

will remove all non-required packages.

2. To install an item both locally and globally use:

   sudo npm install -g phantomjs

Answer 2

1. Yes. (Re-installing with npm install wont install phantom.js again.) (Btw.: npm install xxx --save will automatically add xxx to the package.json)
2. Yes. Local package versions are preferred over global ones. (Although you need some path handling for executables.)