Rectras – Node JS Interview Questions

Here is the list of Node JS Interview Questions which are recently asked in Rectras 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 open source cross-platform for server-side programming that allows users to build network applications. It is used for non-blocking, event-driven servers, due to its single-threaded nature.

2. Explain CLI in Node.js?

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

3. In which Language Node Js is written ?

Node.JS is written in C, C++, and JavaScript.

4. Who is the author of Node Js ?

The author of Node.js is Ryan Dahl

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. For example, the V8 engine is a core component of the Node.

6. Explain V8 Engine ?

The V-8 operates like any other gasoline-powered four-stroke engine. The cylinder pulls in air and fuel, compresses the air and fuel, a spark plug ignites the mixture to create power and forces the piston downward, and the piston pushes exhaust gases out as it travels back up.

7. Explain ECMAScript ?

ECMAScript is the scripting language that forms the basis of JavaScript. ECMAScript standardized by the ECMA International standards organization in the ECMA-262 and ECMA-402 specifications.

8. How can you check the installed version of Node Js ?

To see if Node is installed, open the Windows Command Prompt, Powershell or a similar command line tool, and type node -v . This should print the version number so you'll see something like this v0. 10.35 .

9. Explain What is NPM ?

NPM(Node Package Manager) is a package manager for the JavaScript programming language maintained by npm, Inc. It consists of a command line client, also called npm, and an online database of public and paid-for private packages, called the npm registry.

10. Explain Modules in Node Js ?

In Node.js, Modules are the blocks of encapsulated code that communicates with an external application on the basis of their related functionality. Modules can be a single file or a collection of multiples files/folders.

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11. What are CommonJs Modules ?

CommonJS module is a reusable piece of JavaScript that exports specific objects made available to any dependent code. It contains two primary parts: a free variable named exports , which contains the objects a module wishes to make available to other modules, and a require function that modules can use to import the exports of other modules.

12. For what require() is used in Node Js ?

In NodeJS, require() is a built-in function to include external modules that exist in separate files and reads a JavaScript file, executes it, and then proceeds to return the export object.

13. Explain module.exports in Node Js ?

Node.js is used to export any literal, function or object as a module. It is used to include JavaScript file into node.js applications. The module is similar to variable that is used to represent the current module and exportsis an object that is exposed as a module.

14. Is Node Js Single-threaded ?

Node.js 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.

15. What are events?

Every action on a computer is an event. Like when a connection is made or a file is opened. Node.js has a built-in module, called "Events", where we can create-, fire-, and listen for- your own events. We can assign event handlers to the own events with the EventEmitter object.

16. Explain event loop in Node Js ?

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

17. How to create a simple server in Node js that returns Hello World ?

To get started with a Node.js web application, first need to initialize the project in the project folder on terminal. Open a terminal window and create a new directory called simple_server with mkdir . Initialize the project with npminit.

18. Difference between cluster and child_process modules?

With the cluster module, the creation and sharing of child processes and several parts become easy. In a single thread, the individual instance of node. A developer can access Operating System functionalities by the child_process module, this happens by running any system command inside a child process.

19. How to stop master process without suspending all of its child processes?

Upstart is a process management system with which you can stop the master process.

20. What does emitter do and what is dispatcher?

An Emitter class can be used to raise and handle custom events and it facilitates interaction between objects in Node. A Dispatcher is a service object that is used to ensure that the Event is passed to all relevant Listeners.

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TOP MNC's NODE JS INTERVIEW QUESTIONS & ANSWERS

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Rectras Node JS Interview Questions