What is the difference between single-threaded and non-blocking I / O in NodeJs?

Question

I read and looked through as much NodeJs code as possible, but I'm a bit confused about this:

What does Node mean as a single-threaded value, and what does non-blocking I / O mean? I can achieve the first by creating a child process, and the second by using an asynchronous library. But I would like to understand what this means and how non-blocking I / O still slows down your application.

Answer 1

I will try my best to explain.

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