Any recommendations for resources to improve one's Javascript code running on the back-end, for example node.js/V8 or vert.x/JVM.

Specifically: (i) how to leverage Javascript to write better networking code (e,g; cluster, websockets, etc), and (ii) for number crunching on the server-side, should the relevant code be written from scratch in functional Javascript, or is it better to fork a process that runs (say) Julia code?