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Top Node.js Interview Questions and Answers

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With all the boosting interest in JavaScript, the planet has noticed a groundbreaking change in web growth. The task and methods of web designing have considered a remarkable turn. JavaScript operating on the server what about the internet browser has opened new possibilities and also helped us realize ways we were not conscious of.

  1. What’s node.js? Exactly how node.js works?

Node.js is an open source, cross platform runtime environment for developing server side and networking programs written in JavaScript. It’s the archetype of a scalable and customizable exceedingly tech. JS is designed using single threaded, non-blocking-based I/O models and event-based architecture. It’s composed of Google Chrome’s V8 engine written in multiple platform C library i.e Libuv and C which backs asynchronous I/O based events on event loops plus thread loops. Although Node.js is pronounced of Libuv, it is able to nevertheless be utilized in pure JavaScript.

  1. Where could we work with node.js?

Node.js may be worn at an assortment of platforms. A number of examples are stated below:

Backend for Social Media Networking – LinkedIn
Single-page Application – GitHub
Chat Application –
Data Streaming – Netflix
IoT Application – PREE

  1. What’s the benefit of using node.js?

Node.js is utilized by professionals and several really renowned companies as Uber and Netflix. Evidently, it offers features that cause it to be the very best. Below mentioned are a few benefits of using Node.js

Easy to learn due to the accessibility of its and object oriented programming.
Easy to use since it just employs 1 language as the catalyst of the full stack development.
It’s Faster to deploy, as programs and also sites made with Node.js call for a shorter time on development thus lowering the general time-to-market.
Node.js is a scalable option to Apache. It is able to manage different concurrent connections and distribute tasks skillfully amongst resources.

  1. What exactly are the 2 kinds of API functions in Node.js?

Node.js has 2 varieties of API functions

Asynchronous, Non blocking functions
Synchronous, Blocking functions

  1. What’s control flow function? Explain the actions how “Control Flow” regulates the functions calls?

The order where the execution of statements is accomplished by the pc is known as Control Flow. The control flow function in Node.js is a code which is used between Asynchronous function calls. Below provided are steps that are used to use Control Flow Function.

Execution order has to be controlled
Gather the necessary data
Concurrency has to be limited
Next, the system is requested

More questions can be seen here:

  1. Why is Node.js rapidly increasing attention from JAVA programmers?

The reason for Node.js quickly becoming more popular is the loop-based server of its for JavaScript. Node.js has the developer the center to create JavaScript on the server.

  1. What’s the event loop in Node.js work? And just how does it function?

The I/O non blocking operation of Node.js is made possible through event loops despite JavaScript is a single threaded language. At the start of the task, Node.js initialises the event loop, processes the provided input script which syncs API calls, schedule timers, then begins processing the event loops.

  1. How are you going to debug an application in Node.js?

Debugging means relieving the code of yours from any kind of error. To identify a mistake is able to use up numerous hours that Node.js has a fantastic tool that will help locating the error.

Open the original file (typically index.js), trigger the Run and also Debug pane, and also simply click the Run and Debug Node.js (F5) button. The debugging display screen is akin to Chrome DevTools with a Variables, Loaded scripts, Call stack, Watch, as well Breakpoints list.

  1. What exactly are several of the most favored modules of Node.js?

Every creator has to be built with the most recent updates and info on software libraries as they create the process of programming super easy. The useful and popular most modules of Node.js are-


  1. What’s a Callback function in Node.js?

Callback function is employed if a job is done. Hence it’s a precaution against any sort of blocking. In the meantime, the callback feature allows some other codes to run. Together with the Callback feature, Node.js becomes vastly scalable because it is able to process a huge amount of requests without awaiting any performance to return the outcomes.

  1. What exactly are the difficulties with Node.js?

Although Node.js is just about the most well known and commonly used open sources software, it’s its own challenges-

The functionality of Node.js is restricted by the large computation tasks and till date Node.js can’t process CPU bound tasks.
There may be Callback issues due to the asynchronous nature of theirs.
Even with having healthy modules, Node.js continue to has immaturity within tools. There are many resources in the npm registry which are not organized well sufficiently.

  1. What’s REPL in Node.js?

REPL stands for Read-Eval-Print-Loop. This’s a virtual environment that will come with Node.js. It’s an easy and quick way to test easy Node.js codes.

  1. What’s an exam pyramid in Node.js?

An exam pyramid is a metaphor that’s utilized to make a lot of software tests of various granularity. For instance, end-to-end testing, system testing, integration testing, component testing, unit testing, UI testing.

  1. Explain the idea of middleware in Node.js.

Middleware is a characteristic which has the permission to access the requested item, requested response and also the following feature in the application’s request response cycle. The middleware function is able to perform several tasks such as; execute code, make alterations to the petition as well as the result items, finish the request response cycle and also phone the other middleware in the stack.

  1. Describe Node.js exit codes.

Exit codes in Node.js are distinct codes that assist in completing the processes. This might include worldwide objects. A few examples of exit code in Node.js are-

Internal JavaScript Evaluation Failure
Deadly Error
Inner Exception
Handler Run time failure
Uncaught fatal exception