Depends where they come from. The average Python or Perl library seems better written and more tested that something I would write myself. JavaScript seems to have a lot less quality in my experience.
In my opinion, the biggest security liabilities in Node are with npm:
1. The culture that emphasizes tons of tiny packages, each bringing in dozens of other dependencies managed by multiple maintainers. The increases the attack surface dramatically. All it will take will be one single maintainer of a small package used by dozens of other packages to expose his npm password, and exploit could easily spread to hundreds of node apps in a very short period of time. I'm surprised this hasn't happened already.
2. On a related note, npm's lack of package signing. Most of the other popular dynamic languages (Python, Ruby, Perl) offer or even require package signing. npm does require SSL, but package signing is even more important, since only package signing can prevent the scenario I describe above.
That said, I do see lots of unit testing in node packages, so I can't criticize them there.