Top 30+ Node js Interview Questions and Answers 2025

It involves recording the function calls and events that occur during the execution of the application and analyzing the data to identify performance bottlenecks. A thread pool is a collection of threads that are used to execute tasks in parallel. In Node.js, the thread pool is handled by the libuv library, which is a multi-platform support library that provides asynchronous I/O operations. To implement the test pyramid in terms of HTTP APIs, you can start by writing unit tests for each endpoint in the API. These tests should focus on testing the functionality of the endpoint in isolation without making any external requests or dependencies. Once the unit tests are passed, you can write integration tests that test the interaction between different endpoints and components in the API.

Explain the concept of this in JavaScript.

Create a text file named input.txt with the following content. You will need to provide all the required information about your module. You can take help from the above-mentioned package.json file to understand the meanings of various information demanded.

Speed and Performance:

You really do not need to set up your own environment to start learning Node.js. Reason is very simple, we already have set up Node.js environment online, so that you can execute all the available examples online and learn through practice. Feel free to modify any example and check the results with different options. After extensive development and improvements, Node.js reached its first stable version (0.1.14) in March 2010. With the introduction of npm, Node Package Manager, developers gained access to an extensive repository of packages, significantly enhancing the capabilities of Node.js. Showing incredible pace (close to 100% growth in use every year), Node.js has become a universal platform for web apps.

How does Node.js overcome the problem of blocking of I/O operations?

With our expertise in Node.js development, we can help you build high-quality, performant applications that meet your specific needs and requirements. Contact us today to learn more about how we can help you leverage the power of Node.js for your business. Redis is an Open Source store for storing data structures. It can store data structures such as strings, hashes, sets, sorted sets, bitmaps, indexes, and streams.

What are the main features of Node.js

It is the foundation of Node.js’s non-blocking input/output in Node.js, making it one of the most important environmental features. Ultimately, the versatility and performance of Node.js make it a valuable tool for developers looking to build fast, scalable, and efficient applications. Whether you’re building a simple web server or a complex real-time application, Node.js has the tools and capabilities to help you bring your ideas to life. Its ability to handle asynchronous operations and its support for JSON makes it a great choice for building RESTful APIs that can easily integrate with frontend applications.

JavaScript is defined as the language that is used to make web pages interactive. Node.js is a JavaScript Runtime Environment that allows developers to create server-side applications. Previously, JavaScript was used only for client-side scripting in browsers.

Node.js Explained: What It Is and Why Developers Rely on It

JavaScript language brought many new advantages to backend development with its new runtime environment. Here let me outline some software quality assurance (QA) analyst of the technical features of the Node runtime environment that makes it different than others. As part of the explanation, I am also going to outline other technical aspects of the runtime like the asynchronous, event-driven and non-blocking aspect of Node JS. The important bit to understand right up front is that Node is a “JavaScript runtime”. When JavaScript was first created, it was designed to run in the browser.

Method 1

Unlike traditional servers that spawn multiple threads to handle concurrent connections, Node.js uses a single thread to handle all requests. This approach minimizes overhead and improves performance. Node.js is an open-source, cross-platform runtime environment. It uses event-driven, non-blocking Input/output(I/O) architecture.

• Custom hooks are normal JavaScript functions whose names start with “use” and they may call other hooks.
• Returns a new buffer which references the same memory as the old one, but offset and cropped by the start (defaults to 0) and end (defaults to buffer.length) indexes.
• The crypto module is used for encrypting, decrypting, or hashing any type of data.
• By default, NPM installs any dependency in the local mode.
• In larger projects, custom hooks become a powerful pattern for scalable React architecture.
• But, if the channel is unavailable, all the data cannot be pushed to the memory at once.

Hard JavaScript Coding Questions and Qnswers

An event can be anything, such as typing a key or clicking a mouse button. A call-back function is already registered with the element executes whenever an event is triggered. We have compiled a comprehensive list of junior node js developer common Node.js interview questions that come up often in interviews and the best ways to answer these questions. This will also help you understand the fundamental concepts of Node.js. If you’re interested in harnessing the power of Node.js for your next project, our team of experienced developers at EL Passion can help.