Installing npm from ports

Hello everyone,

I have recently installed www/node and www/npm using portmaster:
$ sudo portmaster www/node www/npm

This installation method causes npm to installed as root and thus install all packages using the root account...

Because this happens, a lot of permission issues arise.
I tried fixing this manually, but this caused npm to freeze the entire system (I/O lock) during installing packages.

Is there anyone that has done this successfully and could you help me set it up correctly?
One step further:

I can change npm to run only for a single user by changing the ownership of the following directory:
$ sudo chown -R USER:USER /usr/local/lib/node_modules/npm

This works, but now I can only use it with that user...

Any other idea's?
Just because packages are installed by root doesn't mean they run as root. Does your root account have a limited umask(1) perhaps? That may prevent the correct permissions being set during the install.