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How do you handle errors in Node.js applications?

Q: How do you handle errors in Node.js applications?

**TL;DR.** Match the handler to the async style: try/catch for async/await , .catch() for promises, the **error-first callback** arg for callbacks, and the 'error' **event** for streams/emitters. Centralize HTTP errors in **error-handling middleware**, distinguish **operational** vs **programmer** errors, and treat the global handlers as last-resort safety nets. try/catch (await) .catch (promise) (err, …) callback</tex

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Error handling is critical for robust applications; this checks practical knowledge.

error handlingasynchronouspromisesbest practices

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Async route + central error middleware

app.get('/user/:id', async (req, res, next) => {
  try {
    const user = await db.user(req.params.id);
    if (!user) throw new HttpError(404, 'Not found');  // operational
    res.json(user);
  } catch (err) { next(err); }                          // forward
});

// One place to log + shape the response:
app.use((err, req, res, next) => {
  log.error(err);
  res.status(err.status ?? 500).json({ error: err.publicMessage ?? 'Error' });
});

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