Contus – Node JS Interview Questions

Here is the list of Node JS Interview Questions which are recently asked in Contus company. These questions are included for both Freshers and Experienced professionals. Our Node JS Training has Answered all the below Questions.

1. Differentiate between JavaScript and Node.js.

JavaScript is a popular programming language and it runs in any web browser with a good web browser. Node JS is an interpreter and environment for the JavaScript with some specific useful libraries which JS programming can be used separately

2. What Is Node.js?

Node JS is a platform built on Chrome's JavaScript runtime for easily building fast and scalable network applications. Node JS uses an event-driven, non-blocking I/O model that makes it lightweight and efficient, perfect for data-intensive real-time applications that run across distributed devices.

3. List down the major benefits of using Node.js?

  • Efficient performance and easy development process.
  • Reusable code and prompt code execution.
  • Ability to handle multiple requests and scale smoothly.
  • Asynchronous and event-driven.
  • Supported by leading companies.

4. What is the difference between Angular and Node.js?

Angular is a front-end JavaScript framework that allows developers to create dynamic web applications, while Node JS is a back-end JavaScript framework that allows writing server-side scripting to build fast & scalable web applications. Node JS and Angular can help to build isomorphic web applications.

5. Why Node.js is single threaded?

Node JS follows Single-Threaded with Event Loop Model inspired by JavaScript Event-based model with JavaScript callback mechanism. So, It is single-threaded similar to JavaScript but not purely JavaScript code which implies things that are done asynchronously like network calls, file system tasks, DNS lookup, etc.

6. How do Node.js works?

Node is completely event-driven. The server consists of one thread processing one event after another. A new request coming in is one kind of event. The server starts processing it and when there is a blocking IO operation, it does not wait until it completes and instead registers a callback function.

7. Where Node.js can be used?

Node JS is used for non-blocking, event-driven servers, due to its single-threaded nature. It's used for web sites and back-end API services, but was designed with real-time, push-based architectures in mind.

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8. How many types of API functions are there in Node.js?

There are two types of API functions: Asynchronous, non-blocking functions - mostly I/O operations which can be fork out of the main loop.

9. What is the difference between Asynchronous and Non-blocking?

An asynchronous call requests a transfer that will be performed in its whole but will complete at some future time. Blocking call control returns only when the call completes. Non-blocking call control returns immediately. Later OS somehow notifies the process that the call is complete.

10. What is package.json?

A package. json is a JSON file that exists at the root of a JavaScript/Node project. It holds metadata relevant to the project used for managing the project's dependencies, scripts, version and a whole lot more.

11. What do you understand by Event-driven programming?

Event-driven programming is a programming paradigm in which the flow of the program is determined by events such as user actions (mouse clicks, key presses), sensor outputs, or message passing from other programs or threads.

12. What is an Event loop in Node.js and how does it work?

Event loop is an endless loop, which waits for tasks, executes them and then sleeps until it receives more tasks. The event loop executes tasks from the event queue only when the call stack is empty and allows to use callbacks and promises.

13. Explain  REPL in the context of Node.js.

REPL stands for Read-Eval-Print-Loop. It is a quick and easy way to test simple Node. js/JavaScript code. To launch the REPL (Node shell), open command prompt (in Windows) or terminal (in Mac or UNIX/Linux) and type node and can now test pretty much any Node.

14. List down the tasks which should be done asynchronously using the event loop?

15. List down the steps using which “Control Flow” controls the function calls in Node.js?

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TOP MNC's NODE JS INTERVIEW QUESTIONS & ANSWERS

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