Wipro – Node JS Interview Questions

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

1. What is Node.js?

Node JS is a platform built on Chrome's JavaScript runtime for easily building fast, scalable network applications and 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.

2. Explain CLI in Node.js?

Command-line interfaces (CLIs) built in Node JS allows to automate repetitive tasks while leveraging the vast Node JS ecosystem and package managers like npm and yarn , these can be easily distributed and consumed across multiple platforms.

3. In which Language Node Js is written ?

Node JS written in C, C++, JavaScript

4. Who is the author of Node Js ?

The author of Node JS is Ryan Dahi.

5. Explain What is a Javascript Engine ?

A JavaScript engine is a computer program that executes JavaScript code. In a browser, the JavaScript engine runs in concert with the rendering engine via the Document Object Model. The use of JavaScript engines is not limited to browsers.

6. Explain V8 Engine ?

An eight-cylinder engine, the V8, is common in pickup trucks, SUVs and sportscars because these engines create a lot of horsepower, torque and are better suited to tow or haul. It has between four and six litres of displacement, depending on the size of the eight cylinders within

7. Explain ECMAScript ?

ECMAScript is the scripting language standardized by ECMA International in the ECMA-262 specification. ECMAScript is a language specification. Many languages follow and implement the ECMAScript specification, e.g., JavaScript, ActionScript, Nashorn. ECMAScript and languages

8. What do you mean by Asynchronous API?

Synchronous/asynchronous APIs are application programming interfaces that return data for requests either immediately or at a later time. In the case of asynchronous APIs, the availability of a resource, service or data store may not be immediate.

9. What are the benefits of using Node.js?

Simple to use.
Easy to Learn.
Faster time-to-market.
Scalable.
Single programming language

10. Is it free to use Node.js?

Node JS is an open-source framework under MIT license.Node.js is a JavaScript runtime built on Chrome's V8 JavaScript engine.

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11. What is REPL in context of Node?

REPL stands for Read-Eval-Print-Loop which 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), typenode and can test pretty much any Node.

12. 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 and used for managing the project's dependencies, scripts, version and a whole lot more.

13. What is Event Loop?

The event loop is what allows Node.js to perform non-blocking I/O operations — despite the fact that JavaScript is single-threaded — by offloading operations to the system kernel whenever possible. They handle multiple operations executing in the background since most modern kernels are multi-threaded.

14. What is purpose of Buffer class in Node?

The Buffer class in Node JS is designed to handle raw binary data. Each buffer corresponds to some raw memory allocated outside V8. Buffers act somewhat like arrays of integers, but aren't resizable and have a whole bunch of methods specifically for binary data.

15. What is Piping in Node?

Piping is a method of transferring data from one stream to other with the help of buffers so that the data transfer process can start as soon as it fills up a buffer. This is a module method to pipe between streams forwarding errors and properly cleaning up and provide a callback when the pipeline is complete.

16. How will you read a file using Node?

Filename holds the name of the file to read or the entire path if stored at other location. Encoding holds the encoding of file. Its default value is 'utf8'. callback_functionis a callback functiion that is called after reading of file.

17. How will you write a file using Node?

There are three ways to write a file:

fs.write(fd, buffer, offset, length, position, callback ) need to wait for the callback to ensure that the buffer is written to disk.
fs.writeFile(filename, data, [encoding], callback)
fs.createWriteStream(path, [options] )

18. How will you close a file using Node?

Close() method is used to close the given file descriptor thereby clearing the file that is associated with it. This will allow the file descriptor to be reused for other files. Calling fs.close() on a file descriptor while some other operation is being performed on it may lead to undefined behavior.

19. How will you get information about a file using Node?

Node. js | fs. readFile() Method

Filename holds the name of the file to read or the entire path if stored at other location. Encoding holds the encoding of file. Its default value is 'utf8'. Callback function is a callback function that is called after reading of file.

20. How will you delete a file using Node?

To delete a file in Node JS use Node FS unlink (path, callback) for asynchronous file operation and unlinkSync (path) for synchronous file operation.

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TOP MNC's NODE JS INTERVIEW QUESTIONS & ANSWERS

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Wipro Node JS Interview Questions