Top 200 Most Asked Node JS Interview Questions for Freshers

According to Ambition Box’s estimates, the salary of a fresher Node JS developer can reach up to INR 7.2 LPA. And, that’s huge! However, to get into a reputed IT organisation, one needs to crack the interview. That’s why knowing about Node JS interview questions is deemed crucial.

It’s not the answers you need to worry about. It’s the concept and understanding of the intent that matters the most. So, here we present you with the 200 most asked Node JS interview questions. If you go through this, you can certainly stand out among all the candidates.

Are you excited to know about them all? Let’s get straight to it!

Most Asked Node JS Interview Questions for Freshers

For better understanding, we will categorise the questions into well-defined sections. This will enable you to tackle these questions effectively. Once you know the topic from which the question is asked, you can easily answer the intent rather than going random about it.

Basic Node JS Interview Questions

1. What is Node JS?

Node JS is a JavaScript runtime environment that allows developers to run JavaScript on the server side using the V8 engine.

2. Is Node JS a Programming Language?

No, Node JS isn’t a programming language. It’s a runtime environment for executing JavaScript.

3. What do you mean by V8 Engine?

V8 is Google’s JavaScript Engine that compiles JavaScript into machine code for faster execution.

4. Why is Node JS popular?

Node JS is popular because it is fast, scalable, non-blocking, and uses JavaScript for both frontend and backend.

5. What is Event-Driven Architecture?

It is a programming model where actions are triggered by events such as system signals or user requests.

6. What is Non-Blocking I/O?

Non-blocking I/O allows Node JS to handle multiple requests without waiting for previous operations to complete.

7. What is scalability in Node JS?

Scalability means the ability of an application to handle increasing users or requests efficiently.

8. What is the difference between Node JS and JavaScript?

JavaScript is a programming language, while Node JS is an environment to run JavaScript outside the browser.

Node JS Interview Questions on Modules and Package Management

9. What is Node Package Manager or NPM?

Node Package Manager is used to install, manage, and share Node JS packages.

10. What is a Module in Node JS?

A module is a reusable block of code that can be exported and used in other files.

11. What is the difference between import and require?

require() is used in Common JS modules, while import is used in ES6 modules.

12. What is packageJSon?

PackageJSon is a file that stores project metadata, dependencies, and scripts.

13. What is Nodemon?

Nodemon is a tool that automatically restarts the Node JS server when file changes are detected.

Core Modules Node JS Interview Questions

14. What is the fs module?

The fs module is used to read, write, and manage files in NodeJS.

15. What is the http module?

The http module is used to create web servers and handle HTTP requests.

16. What is the path module?

The path module helps work with file and directory paths.

17. What is the process object in Node JS?

The process provides information and control over the current NodeJS process.

18. What is global in Node JS?

global is the global namespace object available everywhere in NodeJS.

19. What is __dirname?

__dirname returns the directory path of the current file.

20. What is __filename?

__filename returns the absolute file path of the current file.

Node JS Interview Questions on Asynchronous Programming

21. What is asynchronous programming?

It allows tasks to run in the background without blocking the main thread.

22. What is a callback function?

A callback is a function passed to another function to be executed later.

23. What is a Promise?

A Promise represents the result of an asynchronous operation that may complete in the future.

24. What are async/await?

They are syntactic features used to write asynchronous code in a simpler way using Promises.

25. What is the event loop?

The event loop manages asynchronous operations and executes callbacks when tasks are completed.

26. What is the difference between synchronous and asynchronous code?

Synchronous code executes one line at a time, while asynchronous code allows multiple operations to run simultaneously.

Interview Questions on Express JS and Middleware

27. What is Express JS?

Express JS is a lightweight web framework for NodeJS used to build APIs and web applications.

28. What is middleware in Node JS?

Middleware is a function that processes requests before sending the response.

Node JS Interview Questions on APIs, Web Concepts

29. What is an API?

An API allows different software systems to communicate with each other.

30. What is a REST API?

A REST API is a web service that follows REST principles and uses HTTP methods like GET, POST, PUT, and DELETE.

31. What is the difference between GET and POST?

GET retrieves data from the server, while POST sends data to the server.

32. What is JSON?

JSON is a lightweight data format used to store and exchange data.

33. What is CORS?

CORS allows controlled access to resources from different domains.

34. What is API rate limiting?

Rate limiting restricts the number of API requests a user can make within a time period.

Node JS Interview Questions Regarding Streams and Data Handling

35. What is a stream in Node JS?

A stream is used to process data in chunks instead of loading the entire data into memory.

36. What are the Types of streams in Node JS?

• Readable
• Writable
• Duplex
• Transform streams

37. What is buffering?

Buffering temporarily stores data in the memory before it is processed.

Interview Questions on Event Loop and Execution Control

38. What is the difference between setImmediate() and setTimeout()?

setImmediate() executes after the current event loop phase, while setTimeout() runs after a specified delay.

39. What is the difference between process.nextTick() and setImmediate()?

process.nextTick() executes before the event loop continues, while setImmediate() runs in the next cycle.

Security and Authentication Node JS Interview Questions

40. What is JWT?

JWT (JSON Web Token) is used for secure authentication and data exchange between client and server.

41. What is authentication?

Authentication verifies the identity of a user.

42. What is authorisation?

Authorisation determines what actions a user is allowed to perform.

Database and Backend Architecture Interview Questions for Node JS

43. What databases work with NodeJS?

Common databases include MongoDB, MySQL, PostgreSQL, and SQLite.

44. What is MongoDB?

MongoDB is a NoSQL database that stores data in JSON-like documents.

45. What is Mongoose?

Mongoose is an Object Data Modelling (ODM) library for MongoDB in NodeJS.

46. What is microservices architecture?

It is an architecture where an application is divided into small, independent services.

Interview Questions Regarding Error Handling and Configuration in Node JS

47. What is dotenv?

dotenv loads environment variables from a .env file into the application.

48. What is environment configuration?

It is the process of storing sensitive settings like API keys outside the code.

49. What is error handling in NodeJS?

Error handling manages runtime errors using try-catch, call-backs, or middleware.

50. What is clustering in NodeJS?

Clustering allows NodeJS to use multiple CPU cores by running multiple processes.

Don’t Worry; You will get the Promised 200 Questions. Read on!

It is clear that in an interview, understanding the intent of the question matters more than answering. That’s why we have categorised it into 11 distinct sections. This way, you can better answer these questions and make an outstanding impression in the interview.

We know that there are only 50 Node JS interview questions mentioned here. But don’t worry. Here’s a link to download the 200 most asked questions for freshers.

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