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Request Middleware ​

Problem ​

Implement request middleware in a production-friendly way with @vielzeug/logit while keeping setup and cleanup explicit.

Runnable Example ​

The snippet below is copy-paste runnable in a TypeScript project with @vielzeug/logit installed.

ts
import { Logit } from '@vielzeug/logit';

const httpLog = Logit.scope('http');

export function requestLogger(req, res, next) {
  const start = Date.now();
  const label = `${req.method} ${req.path}`;

  res.on('finish', () => {
    const duration = `${Date.now() - start}ms`;
    const level = res.statusCode >= 500 ? 'error' : res.statusCode >= 400 ? 'warn' : 'info';

    httpLog[level](`${res.statusCode} ${label}`, { duration, ip: req.ip });
  });

  next();
}

Expected Output ​

  • The example runs without type errors in a standard TypeScript setup.
  • The main flow produces the behavior described in the recipe title.

Common Pitfalls ​

  • Forgetting cleanup/dispose calls can leak listeners or stale state.
  • Skipping explicit typing can hide integration issues until runtime.
  • Not handling error branches makes examples harder to adapt safely.