15+ NodeJS interview questions with Solutions for 1 to 2 years expertise
1. What’s Node.js?
Reply: Node.js is an open-source, runtime JavaScript atmosphere constructed on Google Chrome’s V8 engine.
2. What’s Node.js used for?
Reply: Node.js is used to create complicated single-page functions, server-side functions, real-time functions, RESTful APIs, chat rooms, browser video games, and so on.
3. What’s a callback operate?
Reply: A callback is a operate handed to a different operate as an argument. It’s an asynchronous equal for a standard operate. It’s referred to as when a given job is accomplished. Callback capabilities stop any type of blocking.
4. What’s asynchronous programming?
Reply: Asynchronous programming is a design sample during which the code is executed in a non-blocking approach. In asynchronous, code is executed with none dependency and order.
5. What’s NPM?
Reply: NPM stands for Node Package deal Supervisor. It’s a Command Line Interface device used for downloading and publishing packages. It’s a web based repository that hosts a number of JavaScript packages.
6. What’s bundle.json and what’s it used for?
Reply: The bundle.json file holds a number of metadata info concerning the venture. It contains numerous fields corresponding to identify, description, and dependencies. It’s used to present info to the node bundle supervisor to determine the venture in addition to deal with the dependencies related to it.
7. Why ought to we use Node.js?
Reply: We should always use Node.js as a result of:
- It’s asynchronous.
- It’s typically quick and it has nice concurrency.
- It’s simpler to construct scalable community applications with Node.js
- It hardly ever blocks.
8. What’s the that means of event-driven programming?
Reply: Occasion-driven programming is a programming paradigm during which the stream is decided by completely different occasions corresponding to messages from different threads or applications. The applying structure of this programming approach is split into two
sections: 1) Occasion choice 2) Occasion dealing with.
9. What’s callback hell? And methods to keep away from callback hell?
Reply: Callback hell is an issue attributable to in depth nesting of callback capabilities. In such a situation, each callback takes an argument that’s the results of the earlier callbacks. Callback hell might be prevented by utilizing occasion queues and
guarantees.
10. What’s a promise?
Reply: A promise in Node.js is a worth returned by an asynchronous operate. It signifies {that a} course of carried out by the asynchronous operate is accomplished.
11. Clarify middleware?
Reply: A middleware is a sort of operate that has entry to request and response objects. Together with these two objects, a middleware additionally has entry to the operate referred to as subsequent, which is used to name the subsequent middleware operate (if there
is any).
12. Identify the modules used for: a) File operations b) Net-based operations c) Buffer primarily based operations
Reply: The module used for file operations is “fs”, for web-based operations is “http”, and for buffer-based operations is “buffer”.
13. What’s the that means of REPL and why is it used?
Reply: REPL stands for READ, EVAL, PRINT, LOOP. By utilizing the REPL bundled atmosphere, it turns into straightforward to create Command Line Interface (CLI) functions.
14. What’s an occasion loop?
Reply: Node.js is single-threaded. Nonetheless, it might probably carry out non-blocking operations. That is potential due to the occasion loop. The occasion loop permits Node.js to carry out non-block operations by assigning operations to the OS wherever and
at any time when potential.
15. What’s an occasion emitter
Reply: An occasion emitter in Node.js is a category that holds all these objects that may emit occasions.
That is all concerning the continuously requested Node.js interview questions for rookies and other people with 1 to 2 years of expertise in internet growth. As talked about earlier, Node.js is large and a number of other questions might be taken out of it. On this article, we mentioned the 15 generally requested Node.js questions with solutions.
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