What is middleware in Node.js and Express?

What is middleware in Node.js and Express?

Middleware in Node.js and Express refers to functions that execute during the request-response cycle. They can modify the request, the response, or end the request-response cycle.

Can you give me an example of a middleware function?

Sure! Here's a simple example:

app.use((req, res, next) => {
    console.log('Request URL:', req.originalUrl);
    next();
});

This middleware logs the request URL and then calls next() to pass control to the next middleware.

How do I use multiple middleware functions?

You can use multiple middleware functions by chaining them in your Express app. For example:

app.use(middleware1);
app.use(middleware2);

What are some common use cases for middleware?

Common use cases include logging requests, handling authentication, parsing request bodies, and serving static files.