How do you tell an operational error apart from a programmer error, and why would you treat them differently?
A strong answer classifies errors by what the failure says about process state, and gives each class its own recovery path
So operational errors are the failures you kind of expect even when your code is correct. A network timeout, a refused connection, a missing file, a 503 from some downstream service. Your program anticipates those and does something about them, retries, returns an error to the client, falls back to a default. Programmer errors are just bugs. Reading a property of undefined, passing the wrong type, calling an API the wrong way. You can't really handle a bug at runtime, so the standard advice is let the process crash, restart it under a supervisor, and go fix the code. In practice I think teams usually define custom error classes with a flag like isOperational, handle the operational ones close to where they happen, and let everything else propagate up to a top-level handler that logs and exits. The whole point of the distinction is you don't have to wrap every line in a defensive try/catch.