Being a well-informed Node.js developer, you are aware that the interview process can be very challenging. Regardless of whether you have just graduated or have been working for years, it is important to know the right node js coding questions and answers to secure your dream position.

This ultimate guide will walk through various node js coding questions and answers at different levels from beginner to advanced. Get ready to blow away your interviewers and show that you are an expert in the world of Node.js!

Node js coding questions and answers for Freshers

You will be asked the Essential Node.js Interview Questions as a fresher. To help you we collected some node js coding questions and answers to help you pass your interview:

 1- What is the Node.js answer?

This one of the important node js coding questions and answers, as it is important to understand that Node.js is a java script run-time built on Chrome’s v8 JavaScript Engine that allows Java script to be run on the server side.

2- Can you explain the difference between Node.js and JavaScript?

The difference between the two is that JavaScript is only useful for client-side scripting while Node.js is a runtime environment that lets you execute JavaScript code on the server-side.

3- Is Node.js single-threaded?

if you are looking for node js coding questions and answers as an entry level, you can answer saying Although single-threaded, Node.js can handle concurrency through its use of an event driven and non-blocking IO model.

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4- What is the API function supported by Node.js?

This functionality in Node.js allows it to process multiple requests at the same time without blocking the main thread thanks to its asynchronous API functions.

5- Explain the difference between both Synchronous and Asynchronous functions?

Unlike a synchronous function that executes line by line, an asynchronous function does not block execution but rather stores a callback and continues with other execution.

6- Can you explain the module in Node.js?

In node js, modules refer to a reusable unit of code which encapsulates related logic together.

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7- What is the importance of npm and its advantages?

this will be definitely one of the node js coding questions and answers you will need, and you can answer it by saying For instance, npm (Node Package Manager) comes as a default package manager for node js allowing access into an extensive ecosystem of open source libraries and tools

8- Can you explain the middleware?

Middleware in node js refers to any function having access to request object (req), response object (res), and next middleware function in the application’s request-response cycle

9- In what way does Node.js handle concurrency even after being single-threaded?

Node.js ensures concurrency through its use of an event-driven I/O mechanism where it can handle several requests concurrently without getting blocked. In this regard, it uses an event-driven mechanism using non-blocking I/O methods for handling multiple requests simultaneously without blocking otherwise known as traditional multiprocessing or multithreading.

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10- Can you explain the control flow in Node.js?

Control flow in Node.js refers to how statements are executed in a program.

11- What is the event loop in Node.js?

Event loop in node js is a mechanism which keeps checking on events queue for new events and if there are any, executes appropriate callback functions.

12- What is the execution order of control flow statements?

In node js control flow statements are executed sequentially according to their order except asynchronous functions.

13- Can you explain the main disadvantages of Node.js?

This is one of the famous node js coding questions and answers freshers looking for, you can answer it saying Among the major disadvantages of Node.js are that it uses only one thread, does not support CPU-intensive tasks and is difficult to learn for beginners.

14- Can you explain the REPL in Node.js?

The REPL (Read-Eval-Print-Loop) is a JavaScript shell that comes with Node.js to enable developers to execute and test JavaScript codes.

15- How a module in Node.js is imported?

To import module in Node.js you can use require(), e.g., const myModule = require(‘./myModule’);.

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16- Explain the difference between both Node.js and AJAX?

However, the main difference between AJAX (Asynchronous JavaScript And XML), and Node.js is that AJAX is a technique used on client side to update web pages without refreshing the whole page whereas Node.js is a runtime environment for executing javascript server side.

17- Explain the package.json in Node.js?

In node js, there exists package.json which serves as a manifest file containing different metadata associated with the project such as dependencies, scripts, version among others.

18- Explain the method to write hello world using node.js

To write “Hello World” using NodeJS you can create a file like app.js then insert console.log(‘Hello World’); into it then run it by typing node app.js.

19- Can you tell me about the most popular Node.js framework used these days?

This one of the Express JS interview questions, because Today express js has become the most popular framework of node js; which is a minimal and flexible web application framework that provides robust set of the features for both the web and the mobile applications.

20- What are promises in Node.js?

In nodejs promises handle asynchronous operations thus providing an alternative that is more readable and manageable towards traditional callback-based asynchronous programming.

Now you already know the basic Node JS coding questions and answers, you may need to know more especially if you are a developer with experience.

Node js interview coding questions and answers for intermediates

Being a junior with some experience makes it more complicated for you than freshers, as you need to learn more difficult node js developer interview questions to pass the interview. Here are some of the node js interview questions and answers:

21- Can you explain the event-driven programming in Node.js?

This is one of the node interview questions you may be asked as a junior. You can answer by saying that In Node.js, programming events is a way of making a program react to different happenings such as user input, network requests or timer events.

22- Explain the buffer in Node.js?

Buffers in Node.js are used to handle binary data more efficiently than regular JavaScript strings do especially when handling such contents as image or audio files.

23- Can you tell me about the streams in Node.js?

Aa a junior you may need to know that this one of the famous node js coding questions and answers, that you can answer saying Streams in Node.js are an effective way of processing data chunk by chunk instead of at once for ease and efficiency in coding.

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24- What is the crypto module in Node.js?

Node.js crypto module provides features like random number generation, hashing and encryption/decryption among others

25- Explain the callback hell?

Also known as the pyramid of doom, callback hell is a term that refers to deeply nested callbacks which confuse the reader or make the code illegible.

26- What is the use of the timers module in Node.js?

In Node.js, The timers module offers a function or piece of code running after some delay or regularly at given intervals.

27- What is the Difference between setImmediate() and process.nextTick() methods?

setImmediate() schedules something while process.nextTick() schedule something else on next iteration on event loop.

28- Explain the difference between both setTimeout() and setImmediate() method?

While setTimeout() delays execution by specific time setImmediate() defers it until next event loop round.

29- Can you explain  the difference between the spawn() and fork() method?

To create child processes, spawn() is used while fork() is a special case of spawn() used to create child Node.js processes.

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30- What is the use of the passport module in Node.js?

The passport module in Node.js is a middleware commonly used for web applications to handle authentication.

31- Can you tell me more about the fork in Node.js?

We use fork(), in Node.js to model child processes that enable our system to utilize system resources efficiently and increase performance.

32- Explain the three methods to avoid callback hell?

Promises, async/await and Generators are the three main ways to avoid callback hell.

33- Can you tell me about the body-parser in Node.js?

Node.js’s body-parser middleware helps in parsing JSON, URL-encoded or raw request bodies.

34- Explain the CORS in Node.js?

Cross-Origin Resource Sharing (CORS) is a mechanism in Node.js that permits restricted resource on a web page being requested from another domain different from the one where it was served first as well.

35- What is the tls module in Node.js?

For secure network communication, the tls module in Node.js offers an implementation of the Transport Layer Security (TLS) and Secure Socket Layer (SSL) protocols.

Node JS interview questions for experienced professionals

If you are looking for Node JS interview questions for 10 years experience or more, this is the perfect guide for nodejs interview questions for experienced professionals:

36- Can you explain the cluster in Node.js?

In nodejs cluster means spawning child processes which share same server port allowing us to make full use of multi-core systems

37- What are the cluster methods in Node.js?

Examples of some common cluster methods in Node.js include cluster.fork(), cluster.workers, and cluster.on().

38- How can you manage sessions in Node.js?

You can use middleware such as express-session or cookie-session for managing session data on the server side.

39- What are the types of streams in Node.js?

There are Readable streams, Writable streams, Duplex streams and Transform streams in Node.js.

40- What is the method to implement authentication and authorization in Node.js?

In Node.js, middleware such as passport.js or a custom authentication system can be used in implementing authentication and authorization.

41- What are the packages used for file uploading in Node.js?

Some of the popular packages used for file uploading in Node.js include multer, express-fileupload, formidable.

42- What is the difference between bothNode.js and server-side scripting languages like Python?

However, server-side scripting languages like Python are independent programming languages with their own environments and tools unlike Node.js which is a JavaScript runtime environment.

43- What can you do to handle database connection in Node.js?

ORMs (Object-Relational Mapping) libraries like Sequelize or Mongoose can also be used to handle database connections in Node.js or you can interact directly with the database using a driver such as mysql or mongodb.

44- Can you explain the way to read command line arguments in Node.js?

For example, process.argv is an array available out-of-the-box in your Node.js code for reading command-line arguments passed when starting the application.

45- What is the Node.js redis module?

The redis module in Node.js provides a client for the Redis database, allowing you to interact with Redis from your Node.js application.

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46- Can you explain the web socket?

WebSocket is a computer communications protocol for creating a two-way communication channel between the client and server, which enables real-time data transfer.

47- What is the util module in Node.js?

The util module in Node.js provides a variety of utility functions, including methods for debugging and error handling.

48- Explain how you can handle environment variables in Node.js?

To handle environment variables in Node.js, you can use the process.env object or a library like dotenv to load environment variables from a .env file.

49- What is the DNS module in Node.js?

The dns module in Node.js provides an asynchronous DNS resolver, which can be used to look up domain names, IP addresses, and more.

50- Explain the child processes in Node.js?

Child processes in Node.js are separate processes that are spawned from the main Node.js process, allowing for better utilization of system resources and improved performance.

Conclusion

Navigating the world of node js coding questions and answers can be daunting, but with the right preparation and understanding of key concepts, you can set yourself up for success. Remember to practice regularly, stay up-to-date with the latest trends and best practices, and be ready to showcase your problem-solving skills and deep technical knowledge. Good luck with your next Node.js interview!

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