Nodejs Patterns

// Good
async function getUser(id) {
  const user = await db.findUser(id);
  return user;
}

// Avoid raw callbacks or.then() chains

// Sequential (slow)
const user = await fetchUser(id);
const posts = await fetchPosts(id);

// Parallel (fast)
const [user, posts] = await Promise.all([
  fetchUser(id),
  fetchPosts(id),
]);

process.on('uncaughtException', (err) => {
  console.error('Uncaught:', err);
  // Graceful shutdown
  server.close(() => process.exit(1));
});

process.on('unhandledRejection', (reason) => {
  console.error('Unhandled Rejection:', reason);
});

app.use((err, req, res, next) => {
  const status = err.status || 500;
  res.status(status).json({
    error: err.message,
    ...(process.env.NODE_ENV === 'development' && { stack: err.stack }),
  });
});