Top 10 Node.js interview questions and answers in 2023

Do you want to be successfully placed as a Node.js developer in a top Silicon Valley company? Or, do you want to create a team of brilliant Node.js developers? If so, you are in luck. For either of these activities, you need some idea about the type of Node.js interview questions you can ask or be asked. The deck of Node.js advanced interview questions that we have carefully curated will assist you in the same.

Last updated on Mar 3, 2022

Node.js is an extremely popular server-side open-source cross-platform environment. If you are looking to move up the corporate ladder with your Node.js skills, it may be a good idea to prepare Node.js interview questions. This is because the Node.js advanced interview questions may not be easy to crack. We have carefully curated the following list of Node.js advanced interview questions to help you understand the types of questions you could be asked.

Whether you are a candidate preparing for the Node.js interview or a recruiter looking for Node.js developers, the following list of Node.js interview questions will be useful for you.

Node.js interview questions and answers


Mention the benefits of using Node.js.
Below are the main benefits of using Node.js: - The APIs in Node.js are asynchronous which means that they do not cause blockers. This happens due to the Node.js server not waiting for the return of data once an API has been called. It moves on to the next API. Instead, there is a notification mechanism that gets the response from the prior API call. Thus, we can also say that Node.js is event-driven. - Node.js is powered by the Google Chrome V8 JavaScript Engine. This makes code execution in the Node.js library super fast. - Node.js is based on a single-thread model with event looping. The event mechanism in the Node.js library makes it highly scalable because it prevents blockers on the server as compared to other servers that can only handle limited requests. In Node.js, the single thread program can service copious requests compared to something like Apache HTTP Server. - Because of the event mechanism in Node.js, there is no buffering. Instead, the data output occurs in chunks.


Explain global installation of dependencies.
/npm directory stores the globally installed dependencies. While these dependencies can be used in the Command Line Interface or CLI function of all Node.js libraries, they cannot be directly imported in the Node application with the require() command. If you want to globally install a dependency, you can use the -g flag.


Explain how blocking is prevented in Node.js.
Because of the event mechanism in Node.js, a callback function is called every time an event starts. This prevents blocking in Node.js.


How does Node.js handle concurrency if it is single-threaded?
Because of the single-thread model, Node.js prevents bottlenecks and aids programmers in easily writing the code. Internally, there are several POSIX threads for different I/O operations like File, DNS, etc. So, when Node receives an I/O request, it uses one of these threads for the I/O operation. Once the operation is complete, the result joins the event queue. Because of the event mechanism, the event loop starts after each event, checks the queue, and if Node’s execution stack is free, then the loop adds the queue result to it, thus, managing concurrency.


Name some important applications in IT where Node.js can be used.
One of the main applications where Node.js can be used is building real-time web applications. Apart from this, distributed systems for sub-programming collection can also use Node.js. It can be used in general applications as well as complex network applications. One can also use Node.js to create, read, write, or close server files.


What causes server latency and prevents scalability?
In general servers, multiple threads tend to load the system with tasks. These tasks tend to engage the cycles in scheduling the threads and thus, bring latency to the server as well as impose a limit on the number of requests that can be handled, thereby affecting scalability.


Define Control function in Node.js.
The Control function is a generic code that can be run among multiple asynchronous function calls. Due to this code being compatible with the function calls, it can be used for several tasks.


What is the Modularize option and when do you use it in Node.js?
With the help of the Modularize option, users can avoid situation callbacks. The Modularize option splits the callbacks into smaller functions that are independent of each other. However, to make these functions work cohesively, they can be also joined at a later stage.


Explain REPL in Node.js.
REPL stands for Read Eval Print Loop. REPL performs tasks related to reading, executing, printing, and looping. The server contains several ad-hoc Java statements that REPL can help execute. With REPL, the JavaScript can enter the shell post directly and reliably perform tasks like debugging, testing, and experimenting.


Are there any disadvantages of Node.js?
No technology comes without a few disadvantages. Node.js also has a few drawbacks. The main drawback is that Node.js responses can be greatly blocked if an intensive CPU computation is used. In such cases, the multiple thread options are better but they are sluggish in performance. Moreover, if a relational database is used with Node.js, it behaves strangely, preventing favorable outcomes that the users can be sure of. Since Node.js does not support multiple threads, it is better suited for lightweight applications but not large-scale or heavy applications.

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Wrapping up

The above set of Node.js interview questions will be the necessary primer for your Node.js interview. With the help of the above Node.js interview questions you can think of answers to similar questions or if you’re a recruiter, formulate new questions. However, the Node.js interview would not be composed of just the technical Node.js interview questions. The Node.js interview would have a broader scope wherein one would normally be quizzed about their social and life skills too. This can help the recruiter ascertain whether the candidate can survive tough situations and help the co-workers in those situations or not. As a recruiter, you must know how important it is to find someone who gels with the rest of the team.

If you are a recruiter wishing to hire from the top 1% Node.js developers, you can collaborate with Turing. If you are a senior Node.js developer looking for a change of job, you can apply to top US Tech companies on

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