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Adam Lyles Kauffman
14,016 Pointsunderstanding .use
he very briefly discussed .use, but it seems like a very important method in express. im a little confused what it does. would we have to do app.use for each require or only for body-parser? thanks!
1 Answer
Brendan Whiting
Front End Web Development Techdegree Graduate 84,738 Pointsapp.use() is for adding middleware. https://expressjs.com/en/guide/using-middleware.html
An assembly line is a good metaphor for middleware. As the request is moving along to a certain destination, it travels through different middleware processes that can modify the request and do certain logic. Middleware are functions. You can use middleware other people have written by installing and requiring a node module, or you could write them yourself. They can do lots of different things depending on the needs of your app: dealing with sessions and cookies, making sure the user is authenticated, handling errors, making sure the request is over https, redirecting the request to another route, and actually returning a response to the client.