Node.js cluster versus JXcore multithread

You can partially mitigate the risks of single threaded Node by using clustering (although it's still tagged an experimental feature) [1].

Also, these worker threads can be made to respawn on a shutdown caused by - let's say - an unhandled exception as [2].

Well by experimental feature the Node.js team means that the API to access clustering features isn't set in stone - not the stability of the code.

JXcore isn't on my radar until it is open sourced with a permissive license.

I'm curious how either of these compare to say Passenger?

how can Passenger help with multi-threading/workers/... ? if a Passenger dev is nearby... i'm curious about it.

Passenger can manage multiple node processes for the same "app" automatically.

So while it isn't multi-threaded it can achieve some of the same goals (better use of multiple cores to serve more requests)