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.
I don't think the server part is necessary. Regardless of where you run it, it relies on ldapjs to talk LDAP to Active Directory.
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.