Concurrency vs Parallelism
Node.js has long excelled at concurrency. With the recent release of Node 13.0, Node now has a stable answer to parallelism as well.
Concurrency can be thought of as switching between async processes, which all take turns executing, and, while idle, return control back to the event loop. On the other hand, parallelism is the ability for a process to separate and run simultaneously on multiple threads. There are other solutions in JavaScript that have tried to address this problem. For an in-depth comparison, I found this article useful.