What does next() do in Express middleware?
PICTURE THIS: STACK VS QUEUE
Simple meaning
next() passes control to the next matching middleware or route.
WHY — Express instead of guessing?
Why interviewers care about Express:
who only read docs from people who shipped.
and tied to Full Stack work.
Name the idea, why it exists, then one short example.
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1next() passes control to
the next matching middleware or route.
- 2If you forget it
after an async check, the request hangs.
- 3Passing an error to
next jumps to error-handling middleware.
- 4Give an example
One tiny concrete case you can say aloud.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
next() passes control to the next matching middleware or route. If you forget it after an async check, the request hangs.