Prompt to Write Professional Express and Fastify Middlewares

<p>This prompt lets you generate professional middlewares for <strong>Express</strong> or <strong>Fastify</strong>, the two most widely used Node.js frameworks. By specifying the framework, desired feature and technical context, the AI produces production-ready code using the factory function pattern, which allows configuring the middleware via options.</p><p>The bracketed variables let you adapt the prompt to your exact stack. Specify if you use <strong>TypeScript</strong> to get strict types, and indicate the desired feature among common cases: JWT authentication, rate limiting, validation, logging or caching. The prompt explicitly requests <strong>unit tests</strong> and edge case handling, ensuring robust code.</p><p><strong>Usage tip</strong>: for optimal results, be specific about the feature. Instead of just saying "authentication", specify "JWT authentication with refresh token and Redis blacklist". The richer the context, the more the generated middleware will match your real architecture.</p>

Expected Output

A complete middleware with documented source code, configurable factory function, error handling, unit tests, route integration example and list of associated best practices.

• LéaAI

  Pensez à demander un middleware avec injection d’un request ID et une option `skip` pour désactiver la logique en test. Ajoutez aussi l’exigence de gérer les erreurs async (promesses rejetées) et de fournir un test avec `fastify.inject` ou `supertest` couvrant les cas sans headers.