Well, with very high probability, your logic is broken in the face of errors / malicious users then.

Node's async structure is just taking the async model of the web one step further, into processing the same request asynchronously if you need to wait for something else.

You might be master of doing this logic right, but I've audited tens (perhaps hundreds) of systems, and all the synchronous ones got it wrong.

(Disclaimer: I've never worked with Node. But I've been writing async servers in C and Python since 1999).