Most common Node.Js interview questions and answers to secure a job at top IT company in Surat

In the last few years, the app development market has changed dramatically. App development companies seize more complex projects than ever. And to deliver such complex projects, they have to employ some of the very latest and most effective development technologies. Node.Js is one of them. 

Node.Js is a very serviceable technology that every mobile app development company is using for the sake of accomplishing tasks easily and delivering projects within the deadline. So, many IT firms are actively looking for more Node.Js developers to be capable of seizing more complex projects which opens many doors of opportunity for Node.Js developers.  

What is Node.js?  

Node.Js is an open-source, cross-platform, Javascript Runtime Environment which enables developers to use JavaScript to write command-line tools and for server-side scripting. It was written by Ryan Dahl in 2009 with an ambition to end an era where limited possibilities of web server, difficulty to handle concurrent connections and very common way of creating code weren’t rare things. Soon after its inception, it became the ultimate choice of developers to build lightweight and highly scalable mobile and web applications. Top companies like IBM, LinkedIn, Microsoft, Netflix are using Node.Js to present better user experience to their users. 

Why you should learn Node.Js? Or usefulness of Node.Js 


According to the most recent survey carried out by Stackoverflow, 49.9% of developers voted Node.Js as their most preferred development technology or framework.  

And there are several reasons behind its popularity. 

  • It lets developers write JavaScript code (on both client and server) 

JavaScript is the most fundamental need to be a developer. Almost all developers start their careers by learning JavaScript. So, it is very obvious that they would love a framework that allows them to write JavaScript code on both client and server. In other words, you don’t need to burn the candle from both sides to learn Node.Js if you’ve already used JavaScript even in the simple project. 

  • Node.Js cuts the complexity by reducing the lines of code 

Using Node.Js, developers can build powerful applications without writing complex code and this is probably the only reason behind its mass adoption. It has the asynchronous-driven architecture which effectively handles data between client and server by processing multiple requests at a time. It also uses V8 JavaScript Engine which is used in Node.Js runtime environment. 

  • Node.Js is very purposeful 

Unlike many other frameworks or development technologies, Node.Js does not serve a single purpose. It is being used in mobile app development, website development and even in IoT projects. Amid skyrocketing IoT market, having expertise in Node.Js can surely help you to get rid of the worry of your career! 

Top Node.Js interview questions and answers 


Following are the top Node.Js interview questions and their answers you should read before appearing in an interview.  

Question 1: If we hire you as the Node.Js developer, where you’ll use Node.Js? 

Answer: Node.Js can be used to accomplish many complex tasks. It can be used to develop web applications, REST API server, and real-time chat applications. Thanks to its ecosystem, we can also develop a mobile app using Node.Js. 

Question 2: Explain the event-driven programming. 

Answer: When we are developing an application that gives output based on the event, like click or keypress, it is called that we are using an event-driven programming method. It mainly follows a publish-subscribe pattern. 

Question 3: What is REFL in Node.Js? 

Answer: REFL means Real-Eval-Print-Loop and it is the virtual environment. The sole purpose of the REFL is to test the JavaScript code. In order to launch REFL, you just need to write a node in command prompt. 

Question 4: What is NPM in Node.Js? 

Answer: NPM means Node Package Manager. It is the online repository of packages. When we install the Node.Js, it gets installed automatically. Through the package. Json file, NPM installs all dependencies of the project. It can even install and delete the packages. NPM owns more than 580000 packages. 

Question 5: How you can update NPM to the new version in Node.Js? 

Answer: By writing the following command: 

$ sudo npm install npm -g
/usr/bin/npm -> /usr/lib/node_modules/npm/bin/npm-cli.js
[email protected] /usr/lib/node_modules/npm

Question 6: What is Callback in Node.Js? 

Answer: Callback is nothing but a function. By giving the Callback function, we allow other code to run in the meantime and prevent blocking. Since Node.Js is the asynchronous platform, the Callback platform plays a major role. 

Question 7:  What is Callback Hell in Node.Js? 

Answer: When a developer uses many Callbacks in the program which results in unreadable code, it is called Callback Hell.


Question 8: What is Chaining in Node.Js? 

Answer: When the output of the one Stream is connected to another stream, it is called chaining.  

Question 9: What is the Exit Code in Node.Js? List out some Exit Codes

Answer: Exit Codes are used to end the process. Unused, Uncaught Fatal Exception, Non-Function Internet Exception Handler are examples of Exit Codes. 

Question 10: How to debug an application in Node.Js? 

Answer: By using a debugging utility called debugger, we can debug the application. To enable it, you are required to start Node.Js with debug argument followed by the path. 

Question 11: What is Crypto in Node.Js? 

Answer: Crypto provides classes like Hash, cipher, sign and verify. Using these classes, a developer can create Encryption and Decryption.

Question 12: Why are we using Timers in Node.Js? 

Answer: Timers execute the code after a certain time. Major three methods of the Timers are setTimeout(), SetImmediate() and SetInterval().   

Question 13: How can you secure your Node.Js application? 

Answer: Node.Js offers many security mechanisms. Authentication checks the identity of users through more than one security check. Session-based and token-based are the two types of Authentication. Additionally, Request Validation makes sure every incoming data is genius. Not only this, but we can also use some tools like Helmet which sets the HTTP headers, Csurf which rejects invalid incoming token, and Node rate limiter which limits the rate of repeated requests.  

Node.Js developer job In Surat 

Coruscate is the top mobile app development company based in Surat. We are doing justice with global clients and local talents in the best possible way. With our high-schooled developers and our positive attitude towards some of the very challenging tasks, we have successfully delivered 200+ projects and disrupted the whole market of FinTech and Micro-Mobility.

We are currently at the top IT company in Surat – Coruscate Solutions – hiring Node.Js developers to strengthen our team and achieve some impossible tasks. So, if you want to be part of the revolution, you can know more about the position and apply online from here. You can also share this post and spread the knowledge of this opportunity.   

Let’s build your own app

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