Problem Statement
Where should the middleware.js file be placed in a Next.js project?
Explanation
Middleware must be placed in a middleware.js or middleware.ts file at the root of your project (same level as pages or app) or inside the src directory if you're using that structure, and it runs before every request is completed. Middleware allows you to run code before a request is completed to modify the response, redirect, rewrite URLs, add headers, handle authentication, implement A/B testing, or block requests based on conditions. It runs on the Edge Runtime for low latency and can use the matcher config to specify which paths it should run on.
