It should also be pointed out you rarely need to edit the package.json manually:

npm init: Prompts for basic/common package.json entries

npm install --save: Install a module and place into dependencies

npm install --save-dev: Install a module and place into dev dependencies

npm install --save-optional: Install a module and place into optional dependencies

http://blog.timoxley.com/post/22371787222/handy-new-options-...