I am not very proficient in javascript so excuse my idiotic questions but how does this work ? Does this need to talk to some low level api or nodejs supports this or ?
You would download and run this on a Node server. It then uses LDAP to talk to Active Directory, and exposes a Javascript library to make that talk simple.
LDAPJS is neat. You can actually run an LDAP server in NODE. I haven't played with it too much, but that's one of those things I just didn't think I would see.
It's an npm package for use with node.js. I don't think it will work in a browser as-is. It's funny, but my initial assumption these days is that it will be exposed via npm and work in node and/or browser via bundling.