What is Express middleware and how does it work?

What is Express middleware and how does it work?

Express middleware are functions that have access to the request, response, and next middleware function in the application. They can modify the request and response objects, end the request-response cycle, and call the next middleware function.

Can you give me an example of a simple middleware function?

Sure! Here's a simple logging middleware:

app.use((req, res, next) => {
  console.log(`${req.method} ${req.url}`);
  next();
});

This logs the HTTP method and URL of each request.

How do I use multiple middleware functions?

You can use multiple middleware functions by calling app.use() for each one. They will be executed in the order they are defined.

What are some common use cases for middleware?

Common use cases include logging, authentication, error handling, and serving static files.