Because we were talking about HTTP server frameworks, it seemed not that problematic to mention one of the most surprising things I've seen in this space. Not n

Because we were talking about HTTP server frameworks, it seemed not that problematic to mention one of the most surprising things I've seen in this space. Not necessarily JS bashing, but sorry for that anyway. I'm surprised to see that it's now gone too! The exact commit is [1], which happened before Express.js 4.7, and you can search for the variable name `arity` in any previous versions to see what I was talking. It seems that my memory was slightly off as well, my bad. The correct description would be that older versions of Express.js used to distinguish "error" callbacks from normal router callbacks by their arities, so `(req, res)` and `(req, res, next)` would have been thankfully okay, while any extra argument added by an accident will effectively disable that callback without any indication. It was a very good reason for me to be surprised and annoyed at that time. [1] https://github.com/expressjs/express/commit/76e8bfa1dcb7b29389c55d55d2072491edbccd91 https://github.com/expressjs/express/commit/76e8bfa1dcb7b293...