In bug 968531, someone reported that the npm(ansi) provides didn't get applied automatically in nodejs-ansi-0.1.2-7.el6. I'm opening this bug so I don't forget to investigate the root cause of this issue and make sure nothing like this happens in the future.
and https://bugzilla.redhat.com/show_bug.cgi?id=970025
This was a temporal issue with the EPEL 6 buildroot. I've rebuilt most of the affected packages already; using this bug to track the few I don't have ACLs for.