Node.js Interview Questions And Answers | Node.js Interview Questions | Node.js Training|Simplilearn

1. General React Questions

2. Beginner Node.js Questions

3. 1 What is Node.js? • Node.js is an open-source, cross-platform JavaScript runtime environment and library for running web applications outside the client’s browser

4. Click here to watch the video General React Questions

5. 1 What is Node.js? • Node.js is an open-source, cross-platform JavaScript runtime environment and library for running web applications outside the client’s browser • It is used for creating server-side web applications

6. 1 What is Node.js? • Node.js is an open-source, cross-platform JavaScript runtime environment and library for running web applications outside the client’s browser • It is used for creating server-side web applications • Node.js is perfect for data-intensive applications as it uses an asynchronous, event-driven model.

7. 2 How Node.js works? Node.js is based on V8 engine, it is a virtual machine that utilizes JavaScript as its scripting language and achieves high output via non-blocking I/O and single threaded event loop.

8. 3 Where can we use Node.js? Web applications

9. 3 Where can we use Node.js? Distributed systems Web applications

10. 3 Where can we use Node.js? Distributed systems Network applications Web applications

11. 4 What do you understand by the term I/O? • The term I/O is used to describe any program, operation or device that transfers data to or from a medium and to or from another medium

12. 4 What do you understand by the term I/O? • The term I/O is used to describe any program, operation or device that transfers data to or from a medium and to or from another medium • Every transfer is an output from one medium and an input into another. Medium can be a physical device or network or files within a system

13. Explain the difference between frontend and backend development? 5

14. Explain the difference between frontend and backend development? 5

15. Explain the difference between frontend and backend development? 5

16. Explain the difference between frontend and backend development? 5

17. 6 What is NPM? • NPM stands for Node Package Manager

18. 6 What is NPM? • NPM stands for Node Package Manager • NPM is responsible for managing all the packages and modules for Node.js

19. 6 What is NPM? • Node Package Manager provides two main functionalities: • It provides online repositories for node.js packages/modules which are searchable on search.nodejs.org

20. 6 What is NPM? • Node Package Manager provides two main functionalities: • It provides online repositories for node.js packages/modules which are searchable on search.nodejs.org • It also provides command line utility to install Node.js packages, does version management and dependency management of Node.js packages

21. 7 What are modules in Node.js? • Modules are like JavaScript libraries that can be used in a Node.js application to include a set of functions

22. 7 What are modules in Node.js? // CREATING A WEB SERVER // Include modules var http = require(‘http’);  var server = http.createServer(function(req, res){ //write your code here }); server.listen(2000); • Modules are like JavaScript libraries that can be used in a Node.js application to include a set of functions • To include a module in a Node.js application, use require() function with the parenthesis containing the name of the module

23. 7 What are modules in Node.js? • Node.js has many modules to provide basic functionality needed for a web application • Some of them are mentioned in this table

24. Why is Node.js being preferred over other backend technologies like Java and PHP? 8 • Node.js is really fast

25. Why is Node.js being preferred over other backend technologies like Java and PHP? 8 • Node.js is really fast • Node Package Manager has over 50,000 bundles for at the developers’ disposal

26. Why is Node.js being preferred over other backend technologies like Java and PHP? 8 • Node.js is really fast • Node Package Manager has over 50,000 bundles for at the developers’ disposal • Perfect for data intensive, real-time web applications as Node.js never waits for an API to return data

27. Why is Node.js being preferred over other backend technologies like Java and PHP? 8 • Node.js is really fast • Node Package Manager has over 50,000 bundles for at the developers’ disposal • Perfect for data intensive, real-time web applications as Node.js never waits for an API to return data • Better synchronization of code between server and client due to same code base

28. Why is Node.js being preferred over other backend technologies like Java and PHP? 8 • Node.js is really fast • Node Package Manager has over 50,000 bundles for at the developers’ disposal • Perfect for data intensive, real-time web applications as Node.js never waits for an API to return data • Better synchronization of code between server and client due to same code base • Easy for web developers to start using Node.js in their projects as it is a JavaScript library

29. 9 What is the difference between Angular and Node.js?

30. 9 What is the difference between Angular and Node.js?

31. 9 What is the difference between Angular and Node.js?

32. 9 What is the difference between Angular and Node.js?

33. 10 Which database is more popularly used with Node.js? MongoDB is the most popularly used database used with Node.js, it is a NoSQL, cross-platform, document-oriented database that provides, high performance, high availability, and easy scalability

34. 11 Mention a couple of popular libraries used in Node.js? Express is a flexible Node.js web application framework which provides a wide set of features to develop both web and mobile applications

35. 11 Mention a couple of popular libraries used in Node.js? Express is a flexible Node.js web application framework which provides a wide set of features to develop both web and mobile applications Mongoose is also a Node.js web application framework that makes connecting an application to a database a much simpler task

36. 12 What are the pros and cons of Node.js?

37. 12 What are the pros and cons of Node.js?

38. 12 What are the pros and cons of Node.js?

39. 12 What are the pros and cons of Node.js?

40. 13 What is the command used to import external libraries? • Command require is used for importing external libraries, for example, “var http=require (“http”)”. This will load the http library and the single exported object through the http variable varhttp = require('http');

41. Intermediate Node.js Questions

42. 14 What does event-driven programming mean? • Event-Driven programming approach exceedingly uses events to trigger various functions. An event can be anything, such as the pressing of a key or clicking of a mouse button

43. 14 What does event-driven programming mean? • Event-Driven programming approach exceedingly uses events to trigger various functions. An event can be anything, such as the pressing of a key or clicking of a mouse button • A call-back function already registered with the element is executed, whenever an event is triggered

44. 15 What is an Event Loop in Node.js? • Asynchronous callbacks are handled by an event loop in Node.js. It is the foundation of the non-blocking input/output in Node.js, making it one of the most important features of the environment Event Loop

45. 16 What is an Event Emitter in Node.js? constEventEmitter = require('events'); classMyEmitterextendsEventEmitter { } constmyEmitter = newMyEmitter(); myEmitter.on('event', () => { console.log('an event occurred!'); }); myEmitter.emit('event'); • EventEmitter is a class which holds all the objects that can emit events • Whenever an object from the EventEmitter class throws an event, all the attached functions are called upon synchronously

46. 17 What are the two types of API functions in Node.js? • Two types of API functions in Node.js: • Asynchronous, non-blocking functions

47. 17 What are the two types of API functions in Node.js? • Two types of API functions in Node.js: • Asynchronous, non-blocking functions • Synchronous, blocking functions

48. 18 What is package.json file? • The package.jsonfile is the heart of a Node.js system

49. 18 What is package.json file? • The package.jsonfile is the heart of a Node.js system • This file holds the metadata about a particular project

50. 18 What is package.json file? • The package.jsonfile is the heart of a Node.js system • This file holds the metadata about a particular project • package.json is present in the root directory of any Node application or module