[wkyleg]

Nobody really uses multithreading for node. I mean I'm some projects do (maybe pnpm?) but the threading support isn't great and the event loop performs well.

[pier25]

Almost everyone running Node in a machine with multiple cores is using multithreading.

Node is multithreaded by default. I believe the default setting is using 4 threads. Most of Node is written in C++.

The JS code written by end users is single threaded (most of it at least) but IO etc is all executed with libuv.

https://docs.libuv.org/en/v1.x/threadpool.html#threadpool