As I mentioned PHP: In PHP each worker is single threaded, too, but you can scale by having more workers in isolation.
Some addition, subtraction is fine. But Array iteration, JSON encoding-decoding and similar CPU bound tasks could block the event loop.
You can perform them asynchronously, or forward the request to some remote service that's better at doing these computations for you and return results (maybe some service written in Python or a database)
Sure, JavaScript (and Ruby and Python) are usually fast enough with modern hardware - but we can't pretend there's no cost.
If my apps were that way, i could have replaced my team with 20 well-fed monkeys.
Does HN think putting 2-15KB JSON blobs in a Postgres DB running on Docker on a router is a good idea? Oh, and the table stores log data, so there's about 2 million rows after 5 days uptime. What do you think?
EDIT: This was not entirely related but it goes to the notion that it seems like a lot of myopic decision-making has somehow become even more acceptable and I would say this leads to dumb situations as above, and Node.
Making a full API on nginx via lua sounds crazy but it appears that people do it.