Shared resource handling with NodeJS?

Event loops etc. is explained in various places but can someone who knows c++ concurrency concepts explain how do we protect our shared resources in let’s say express web server?

Do we need to make sure every asynchronous operation from custom to library have javascript equivalent of MUTEX if such a thing exists?

Here is an answer about express concurrent example and explanation of concurrent request handling, but it does not clarify shared resource problems/protections of those below C++ threads.

Thanks in advance.