Where can I find comprehensive documentation of the command line switches/options for npm?

[b-fuze]

This seems to be a very hard thing to Google, so I'm asking here. Where can I find a comprehensive list of command line switches accepted by each npm command? Does npm $CMD ---help list all of them? Also, what about the root npm command? Are there general switches that are accepted before supplying each command, similar to how -P to git -P $CMD disables paging for example? If so, where can I find the documentation for them?