What is middleware in Express?
Model answer
Middleware is a function (req, res, next) that runs between receiving a request and sending the response. It can read or change req and res, end the response, or call next() to pass control on. Examples: logging, parsing JSON, authentication, CORS and error handling. Order matters because they run in the order registered.
Learn this topic
Express Middleware Explained: next(), Logging and express.json() in the course Node.js and Express: Build a Back End API from Scratch.
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