What is Express middleware and how does it work?

What is Express middleware and how does it work?

Express middleware are functions that execute during the request-response cycle in an Express application. They can modify the request, the response, or end the request-response cycle.

Can you give me an example of a middleware function?

Sure! A simple example is a logging middleware that logs the request method and URL. Here's how it looks:

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

What are some common use cases for middleware?

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

How do I create my own custom middleware?

To create custom middleware, define a function that takes req, res, and next as parameters, and use app.use() to register it.