
Deno Web Development
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If you have used any HTTP framework, be it JavaScript or otherwise, you are probably familiar with the concept of middleware functions. If you are not, then no worries – that's what we'll explain in this section.
Let's start with a definition borrowed from the Express.js documentation (http://expressjs.com/en/guide/writing-middleware.html):
"Middleware functions are functions that have access to the request object (req), the response object (res), and the next middleware function in the application's request-response cycle. The next middleware function is commonly denoted by a variable named next."
Middleware functions intercept requests and have the ability to act on them. They can be used in many different use cases, as follows: