having written a fair amount of lua code, there aren't many libraries out there. Their npm equivalent is called 'luarocks'. To give you an idea of how old the libraries are: many of them mention the perl package it was translated from.
The reason for that of course is that it's so trivial to embed it in a C program, that if you want a library you can just expose a C library in lua. luajit even makes this absurdly easy with its FFI api.
Right, but libraries consist of many other things, including ORM or testing suites. There aren't many great ORM libraries written in C, and you need the test suite to work in lua because you're testing lua code. In general, the world of lua is pretty small, probably smaller than languages like Clojure or OCaml.
The fact that many libraries are "translated from" Perl packages does not mean they are old, it means a significant part of the Lua community has used Perl before. Actually, because Lua 5.2 has been released recently and broke compatibility, libraries that support it are by definition not "old" (or at least they are maintained).
That being said, the community is small and there are indeed way too few libraries available in LuaRocks (slightly over 300). We have been discussing that on the language's mailing list and I will probably talk about it at the upcoming Lua Workshop (http://www.lua.org/wshop13.html).
