Express.js Interview Questions and Answers
Experienced / Expert level questions & answers
Ques 1. Explain the concept of view engines in Express.js.
View engines are used to render dynamic content. Popular view engines for Express include EJS, Pug, and Handlebars.
Ques 2. How can you implement session management in Express.js?
Session management in Express.js can be implemented using middleware like 'express-session' along with a session store.
Ques 3. Explain the purpose of the 'multer' middleware in Express.js.
'multer' is a middleware used for handling 'multipart/form-data,' primarily used for file uploads. It adds a 'body' object and a 'file' or 'files' object to the 'request' object.
Ques 4. How can you implement authentication in Express.js?
Authentication in Express.js can be implemented using middleware like 'passport' along with relevant strategies (e.g., local strategy, OAuth).
Ques 5. Explain the purpose of the 'express-validator' library in Express.js.
'express-validator' is a set of Express.js middlewares that wraps validator.js validator and sanitizer functions, providing validation and sanitation of user input.
Ques 6. How can you implement rate limiting in Express.js?
Rate limiting in Express.js can be implemented using middleware such as 'express-rate-limit' to restrict the number of requests from a client in a given time frame.
Ques 7. What is the purpose of the 'compression' middleware in Express.js?
'compression' is a middleware that compresses the response body for requests that traverse through it, reducing the size of the response and improving performance.
Ques 8. Explain the concept of 'Promise' in the context of asynchronous operations in Express.js.
Promises in Express.js are used to handle asynchronous operations, providing a cleaner and more readable way to structure asynchronous code.
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