Interview Q&A / Node.js
Node.js interview questions
The event loop on the server, streams, modules and building APIs with Express.
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- How does Express know a middleware is an error handler?
By its arity: an error-handling middleware takes four arguments (err, req, res, next). It must be registered after the routes, and errors reach it through next(err) or a thrown error in synchronous code.
IntermediateQuick answer1 min read