The Ultimate Node.js Interview Questions Bank: Be Interview-Ready

Node.js Interview Questions is your go-to resource for mastering the interview process when it comes to Node.js development. Our blog is dedicated to helping developers like you succeed by providing valuable insights, expert tips, and comprehensive question banks.

You will almost certainly be asked one of these most common Node.js interview questions and answers.

Node.js Interview Questions and Answers for Beginners  

  1. Explain briefly how Node.js functions.

Node.js is a virtual environment program built mainly in the computer language JavaScript. It operates on a minimal V8 environment, which provides capabilities like a non-blocking I/O and a single-threaded event loop.

  1. Where and how is Node.js used?

Node.js is used in a variety of sectors. However, the following ideas have received a lot of praise for their style:

Software running on a network

Sharing adaptive web apps via PCs

Server-Client applications

  1.  Why is Node.js limited to a single thread?

To ensure that work can be done at different times, Node.js has a single-threaded paradigm. This makes programs more scalable and efficient, allowing them to function correctly even with many users.

  1. What are the various API methods that Node.js supports?

API methods are classified into two types. They are as follows:

Using synchronized APIs for non-blocking operations

Asynchronous APIs are used to execute blocking methods.

  1. What is the function of control flow?

The control flow function is a standard code executed whenever an asynchronous function call is performed. It instructs Node.js on how and in what order these functions should be implemented.

  1. Why is Node.js so popular right now?

Because it mainly uses JavaScript, Node.js has multiplied. Programmers can select from the following alternatives:

When JavaScript code is placed on a server, TCP and other protocols provide direct access to a database via File I/O entities in the HTTP stack.

  1.  What exactly is a test triangle?

A test pyramid displays the number of test cases run during unit, integration, and combination testing (in that sequence). This is kept up to date so that as a project grows, there are enough test cases to run.

  1. Why does Google’s Node.js use the V8 engine?

Google uses the V8 engine to convert JavaScript into a low-level language swiftly. This is done to ensure that apps work smoothly and that consumers may connect with them in real-time.

  1. What are global objects in Node.js?

Global objects in a Node.js program are those with a scope that may be seen from any node. The items will not be required in every module. One of the artifacts contains a universal message. This allows functions, texts, and objects to be utilized everywhere in the program.

The second thing you should consider in Node JS code is how to use files.

  1. Why does Google’s Node.js use the V8 engine?

Google uses the V8 engine to convert JavaScript into a low-level language swiftly. This is done to ensure that apps work smoothly and that consumers may connect with them in real-time.

NodeJS Interview Questions and Answers for Experienced 

  1. What types of streams are available in Node.js?

Node.js can manage a variety of streams, including:

Both English and Spanish are available for streaming.

Streams wrote to Transform (copies for data changes) .

  1.  What exactly does the Node.js REPL do?

REPL is an abbreviation for “read-eval-print-loop.” It allows users to virtualize JavaScript programs created in Node.js.

“node” is a straightforward program that may be used to launch REPL. After that, you can directly type JavaScript jobs onto the command line.

  1. What exactly does “tracing in Node.js” mean?

Tracing is used to collect all tracing data produced by V8, the node core, and the userspace code. All this information is saved in a log file, a wonderful way to ensure the provided data is correct.

  1. Where does package.json appear in Node.js?

Each item in a project’s information is recorded in a file called “package.json.” It can also be used to identify a project and maintain track of all associated materials.

  1. What’s the difference between readFile and createReadStream in Node.js?

readFile is used to read the entire contents of a file without interrupting other tasks. The information will be read into memory before users can use it.

To read the field once it has been split apart, create a ReadStream. The size of the chunks can be modified depending on the situation. By default, 64 KB is used.

  1. What is the purpose of the Node.js crypto function?

Node.js employs the crypto module to provide users with access to cryptographic functionality. This allows individuals to utilize many layers to encrypt, decrypt, sign, and hash data.

  1. What exactly is a Node.js passport?

Passport is a really useful piece of Node.js middleware. It is commonly used for security and easily integrates into any Express. Js-based web application.

Each app will require its method of authentication. Using a passport, this is accomplished as independent modules, making it simple to assign tactics to apps based on their needs while eliminating any form of dependency.

You Must Read: MEAN v/s MERN Stack: All you need to Know 
  1. What is the Node.js EventEmitter used for?

Every emitting object in Node.js comprises a single instance of the EventEmitter class. These items can be linked to named events thanks to a feature they contain.

When the EventEmitter object sends an event, the functions are linked together.

  1. What is the difference between setImmediate() and setTimeout()?

The setImmediate() method is intended to execute a single script as soon as the current event loop completes.

A script can be retained in memory and set to run after a specified amount of time has passed using the setTimeout() function.

The order in which the functions are executed is determined solely by the situation in which they are invoked. If the process were invoked from the main module, the timing would be determined by how well it functions.

Node.js Interview Questions
  1. What is the purpose of the module Exports in Node.js?

The module. The export method exposes two functions and places them in a real-world context. A module is a single piece of code containing related components. Consider this as putting all of the methods into a single file.


Node.js is frequently used to create flexible and fast online apps, APIs, real-time apps, and other network applications. Developers appreciate it because it is simple to use, has an enormous range of modules, and can be utilized in various ways.

Press ESC to close