NodeJS userland is effectively single-threaded, but NodeJS is not single-threaded. NodeJS outsources some event loop scheduling to libuv, and libuv is multi-thr

NodeJS userland is effectively single-threaded, but NodeJS is not single-threaded. NodeJS outsources some event loop scheduling to libuv, and libuv is multi-threaded (by default, 4 threads, but this can be configured. See: https://medium.com/the-node-js-collection/what-you-should-know-to-really-understand-the-node-js-event-loop-and-its-metrics-c4907b19da4c https://medium.com/the-node-js-collection/what-you-should-kn...