Advanced Node.JS Interview Questions

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Node.JS Interview Questions

If you're looking for Node.JS Interview Questions for Experienced or Beginners, you are at right place. There are lot of opportunities from many reputed companies in the world. According to research Node.JS has a market share of about 2.6%. So, You still have opportunity to move ahead in your career in Node.JS Development. Mindmajix offers Advanced Node JS Interview Questions 2018 or node js programming interview questions that helps you in cracking your interview & acquire dream career as Node.JS Developer.

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Q1) What according to you is the scope of NodeJs in the present domain of Information Technology?
The fact is latency, scalability, as well as the reliability is the essential KPI’s in the present world of Information Technology dealing with the web server domain. NodeJs is basically a JavaScript runtime which simply makes sure of high throughput and low latency under all the circumstances. It is based on a non-blocking approach which simply makes sure that no precious time gets wasted on the I/O requests to be acknowledged at the server end. 

Q2) Can you name the two important types of API which you can find in Node.JS approach?
These are, Synchronous which is considered for the blocking functions and second is the Asynchronous which is generally considered for the Non-blocking ones. 

Q3) What are the important applications in the IT in which the Node.Js approach can be considered?
The biggest application of Node.JS is in real time web applications building. In addition to this, it can be considered in distributed systems for sub-programming collection. More applications include its use in general applications and in some complex network applications. 

In addition to this, Node.JS can be used for creating, reading, writing, as well as closing the files on the server. Some users often use it for the purpose of editing the data in the database. Moreover, it has applications when it comes to generating the web page content.

[Related Article: Today’s web is a big-event web - Node.JS  ]

Q4) Name the file you need to run the Node.JS on a windows server?
It is MSI installer and the same can be downloaded from the official website of Node.JS

Q5) What exactly do you know about the Node.JS and how does it work?
It is basically an approach for server side scripting that is very essential when it comes to building the error-free scalable programs. One of the key benefits of this approach is its non-blocking I/O approach that doesn’t let the users face any problem and this is one of the key benefits of Node.JS. It basically works on a V8 environment and is purely based on utilization of the JavaScript for getting the I/O outcomes which are of high quality. The users can easily make sure of the single-threaded event loop.

Q6) In a step-wise manner, tell how the control flow generally control the functional calls in the Node.JS?
The first step towards the accomplishment of this task is to simply control the order of execution. Next is to collect the concerned data from the data warehouse or from the server. After this, a limit is generally imposed on the concurrency and then the sequence of the concerned tasks is to be followed. 

Q7) What does the term I/O means in Node.JS?
Node.JS has an important application with this term. It basically means Input and Output and is generally considered for accessing any feature which is present in the outer environment of the program or the application. It is generally loaded to the machine memory so that the concerned program can be made to run in a very reliable manner. 

Q8) What exactly adds latency in the server and affect the scalability?
Generally, the existence of multiple threads leads to a system which is often loaded with the tasks that generally engage the precious cycles on the scheduling of thread. This is exactly what that add latency and impose a strict upper limit on the scalability. 

Q9) Can you tell something about the event-driven programming and what role does it play in the Node.JS approach?
It is basically a programming paradigm that decides the exact flow of the program. The same is purely and largely based on some of the important events such as sub-programs and messages and sometimes even on threads. Generally, it is considered as an application architecture approach useful for smooth handling of the programs and assuring their effective running. 

Q10) What exactly do you know about a Node.JS file and when it is to be initiated on the server?
It is basically a file that generally provides information on the important tasks that are to be executed in the server environment at different levels. It should be initiated prior to any effect in the server domain. Generally, the events are defined as the process of grabbing the port on the server.

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Q11) How to update a dependency using npm?
Update package.json and change the version of the dependency which to be updated and run the following command.

Q12) Which module is used for web based operations?
http module is used for web based operations.
var http = require(“http”)
fs module provides both synchronous as well as asynchronous methods.

Q13) fs module provides both synchronous as well as asynchronous methods.

Q14) Mention some of the leading benefits of using the Node.JS approach than other similar technologies?
First of all, it is very reliable to work with and is best when it comes to saving a lot of time. Also, it is widely known to build network programs which are highly scalable. All the tasks can be accomplished in a fast way due to its I/O approach and in addition to this; it is capable to synchronize almost everything to get the results far beyond any imagination. Node.JS is also known for its excellent concurrency. The biggest advantage that it offers to the users is that it almost never gets blocked.

[Related Article: In the right place at the right time - Node.JS ]

Q15) Define the Control Function in the Node.JS in your own way?
It is basically considered as a generic code which is capable to be run among the different asynchronous function calls. The best thing about it is its compatibility with the functional calls that makes it useful for different tasks. 

Q16) What is the prime benefit that the Node.JS can offer to the user being a single threaded approach?
It simply make sure of the scalability, as well as performance and this is because asynchronization when done on a single thread help avoiding the typical web loads that often creates issues.

Q17) What are the features of Node.JS you are familiar with?

1. In Node.Js, all the API’s are asynchronous 

2. A Node.JS server never wait for anything

3. There is a notification mechanism that simply let the users get information about the response from the last API

4. It is fast as it is build on the V8 JavaScript engine

5. There is a full fledge library available that help users in proper execution of the code

6. It is based on a single thread model 

7. The Node.JS server can easily handle a very large number of requests without facing the downtime 

8. There is no buffering at all as already mentioned

Q18) What exactly is a module in the Node.JS and is it possible for the users to change the same if the need of same is felt?
A module is nothing but a series or a group of functions that a user needs to include in the concerned program or application. Yes, it is possible to change the same by the users. The users can also create the new modules if the same are required. 

Q19) What is Callback in the Node.JS environment?
It is basically a function that is generally executed at the last stage or during the end of a task assigned to the server. This is useful in enabling the users to run another code in the time being without facing the blocking issue. As Node.JS is an asynchronous platform, it largely depends on the callback option and most of the features it has are based on the same. Generally, it’s the API’s present in the Node.JS which supports it.

Q20) What exactly Global are in the Node.Js and what’s their significance?
This is actually a keyword in Node.JS which is simply considered for the purpose of representing the global namespace object. It is possible to deploy some of them for the module scope and this is one of the best things about them. 

[Related Article: What is Node.js? ]

Q21) While working in the Node.JS environment, which framework you have used mostly?
The answer to this question depends on the overall experience of the user. Generally, the “Express” is the framework which is used commonly so you can answer it against this question. 

Q22) What is Modularize option and when you can use it while working on a Node.JS server?
It is basically an option that simply let the users to avoid the situation callback hell. It does so by simply splitting the callbacks into the functions which are small in size and are generally independent. The functions can be joined at a later stage in order to make them work together.

Q23) Name a few important tasks that you can perform simply with the help of event loop?
A lot of tasks can be performed with the help of this and a few important ones are marinating the Input/output operations, handling blocking, as well as the handling of heavy computation problems.

Q24) What exactly do you know about the REPL in the Node.JS environment?
It stands for the Read Eval Print Loop and is generally engaged in performing various tasks that are related to the Printing, Looping, Reading, as well as executing. A number of ad-hoc Java statements are present in the server that can easily be executed with the help of REPL. The JavaScript can be made to enter directly in the shell post which the tasks such as debugging, testing, as well as experimenting can be performed reliably. 

Q25) Do you think there are some disadvantages of using the Node.JS approach? If so, tell what?
Yes, there are a few drawbacks that are associated. The fact is any intensive CPU computation can block the Node.JS responsiveness upto a great extent. Therefore, a thread platform is a better option but it needs more time and efforts to get the things done in the rightful manner. There are no favorable outcomes that the users can make sure if the relational database is deployed with the Node.JS approach.

Q26) Is it possible in the Node.JS to import external libraries Name the command that can be used for this?
Yes, this is possible and for this, the command “require” is generally considered. 

Q27) While working with the Node.JS server, what you will do in case the problem of blocking of I/O will be there?
The event based model present can directly be inserted at the core of Node.JS sever. Generally, for this task, an event loop is considered rather than considering the threads. 

Q28) Compare Node.JS with Ajax simply
Ajax is a client side approach whereas the Node.JS is a server based approach. It is generally used for updating the contents of the page and the good thing is users need not to worry about the refreshment of the page for this. On the other hand, the same is required in the Node.JS approach for developing the software. Unlike Ajax, it is executed in the server than in browser.

[Related Article: Comparison Between AngularJS vs Node.JS ]

Q29) Mention any one problem which you faced with the technical features of the Node.JS
Sometimes, it becomes difficult for the users to have one process for scaling with the server and this creates issues in the long run. 

Q30) Tell something about the callback hell in the Node.JS environment?
When the heavily nested calls back are considered in the server, this situation arrives and blocks the code up to some extent resulting in its unreadibility and complexity to maintain and run.

Q31) Name a few IDE’s which you can consider for the development of the Node.JS?
This includes:

  • JetBrains WebStorm
  • Cloud 9
  • Komoda IDE
  • JetBrains Intelij IDEA
  • Atom 
  • Eclipse

Q32) What is promise mechanism in the Node.JS approach and what is its significance?
It is basically an approach that is considered for avoiding the callback hell situation. It gives an additional path for writing the async codes and users can simply make sure of avoiding the same in the shortest possible time. 

Q33) Tell some examples of server where you will use the Node.JS and why
The Node.JS technology can be considered in the gaming servers, social media server, streaming servers, advertisement servers, as well as in collaborative servers. This is because these servers have to handle a lot of requests and the Node.JS technology is good enough to be considered in the ones that have large volume of traffic/requests.

[Related Article: Basic Examples of Node.js ]

Q34) Is it free to use Node.js?
Yes! Node.js is released under the MIT LICENSE and is free to use.

Q35) Is Node a single threaded application?
Yes! Node uses a single threaded model with event looping.

Q36) Can we evaluate simple expression using Node REPL

Q37) How to uninstall a dependency using npm?
Use following command to uninstall a module.C:Nodejs_WorkSpace>npm uninstall dependency-name

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Priyanka Vatsa
About The Author

Priyanka Vatsa is a Senior Content writer with more than five years’ worth of experience in writing for Mindmajix on various IT platforms such as Palo Alto Networks, Microsoft Dynamics 365, Siebel, CCNA, Git, and Nodejs. She was involved in projects on these technologies in the past, and now, she regularly produces content on them. Reach out to her via LinkedIn and Twitter. Protection Status