Infosys – Node JS Interview Questions

Here is the list of Node JS Interview Questions which are recently asked in Infosys 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 an open-source, cross-platform, back-end JavaScript runtime environment that runs on the V8 engine and executes JavaScript code outside a web browser.

2. What Do You Mean By Asynchronous Api?

Synchronous/asynchronous APIs are application programming interfaces that return data for requests immediately or at a later time. Asynchronous requests are useful in maintaining functionality in an application rather than tie up application resources waiting on a request.

3. What Are The Benefits Of Using Node.js?

Easy to learn.
Keeping things simple.
Faster time-to-market, Scalability.
Battle-tested old hand, MVP development.
Community.

4. Is It Free To Use Node.js?

Node JS is a cross-platform runtime environment for JavaScript, which is free and open-sourced. It is full-stack can be used to develop both the client-side and the server-side of an application

5. Is Node A Single Threaded Application?

Node JS is single-threaded application but not purely JavaScript code which implies things that are done asynchronously like network calls, file system tasks, DNS lookup, etc.

6. What Is Repl In Context Of Node?

REPL (Read-Eval-Print-Loop) is a quick and easy way to test simple Node. 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.

7. What Is The Difference Of Using Var And Not Using Var In Repl While Dealing With Variables?

If var the variable is declared within the scope you are in (e.g. of the function). If you don't use var , the variable bubbles up through the layers of scope until it encounters a variable by the given name or the global object , where it then attaches.

8. What Is Npm?

Node Package Manager (NPM) is an open-source software library that has over 800,000 code packages. We can say that NPM is a command-line tool that installs, updates, or uninstalls Node. JS packages of an application.

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9. What Is Global Installation Of Dependencies?

The global installation of dependencies in Node JS is putting global packages in a single place in the system exactly where it depends on the setup, regardless of where you run the command NPM install -g

<package-name> to install dependencies

10. What Is Local Installation Of Dependencies?

Install the dependencies in the local node_modules folder. In global mode (ie, with -g or --global appended to the command), it installs the current package context (ie, the current working directory) as a global package. By default, npm install will install all modules listed as dependencies in package.

11. How To Check The Already Installed Dependencies Which Are Globally Installed Using Npm?

Global Modules are generally located at user's home directory, though we can change the path where global modules reside.

Lists local modules within current dir: npm list.
Lists global modules:npm list --global OR npm list --g // It will list all the top level modules with its dependencies.

12. What Is Package.json?

All npm packages contain a file, usually in the project root, called package. json - this file holds various metadata relevant to the project. This file is used to give information to npm that allows it to identify the project as well as handle the project's dependencies.

13. Name Some Of The Attributes Of Package.json?

The dependencies property of a module's Package.JSONis where dependencies - the other modules that this module uses - are defined. The dependencies property takes an object that has the name and version at which each dependency should be used

14. What Is Callback?

Node JS being an asynchronous platform, doesn't wait around for things like file I/O to finish – Node Js uses callbacks. A callback is a function called at the completion of a given task preventing any blocking, and allows other code to be run in the meantime.

15. How Node Prevents Blocking Code?

Node JS is a cross-platform JavaScript runtime environment that helps to execute and implement server-side programs. Node is assumed to prevent blocking code by using a single-threaded event loop.

16. What Is Event Loop?

The event loop 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. Since most modern kernels are multi-threaded and can handle multiple operations executing in the background.

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TOP MNC's NODE JS INTERVIEW QUESTIONS & ANSWERS

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Infosys Node JS Interview Questions