The Top 10 Node.js Interview Questions to Ace Your Placement
Are you prepping for a Node.js interview? Whether you’re a beginner or an experienced developer, it’s critical to brush up on fundamental topics and frequently asked questions. In this blog article, we will go over the top ten Node.js interview questions that you should be prepared for. Read on to learn more and get ready to amaze your interviewer!

1. What is Node.js?
   Node.js is a runtime environment that lets you run JavaScript code on the server. Node.js, based on the V8 JavaScript engine, is notable for its event-driven, non-blocking I/O paradigm, which makes it lightweight and efficient.
2. How does Node.js handle asynchronous operations?
   Node.js uses an event-driven architecture and a non-blocking I/O model. Asynchronous operations are handled via callbacks, promises, or async/await syntax, allowing the server to handle multiple requests simultaneously without waiting for any single operation to complete.
3. What is the purpose of the package.json file?
   The package.json file is the heart of a Node.js project. It contains metadata about the project, including the project name, version, dependencies, scripts, and more. This file is essential for managing the project and its dependencies.
4. Explain the event loop in Node.js.
   The event loop is a fundamental concept in Node.js. It’s a loop that picks up tasks from the event queue and executes them. The event loop ensures that Node.js can handle asynchronous operations efficiently by processing callbacks and other asynchronous events.
5. What is middleware in Express.js?
   Middleware functions in Express.js are functions that have access to the request object, response object, and the next middleware function in the application’s request-response cycle. They are used to modify the request and response objects, end the request-response cycle, and call the next middleware function in the stack.
6. How do you handle errors in Node.js?
   Error handling in Node.js can be done using try-catch blocks, promises, and the error-first callback pattern. Proper error handling ensures that the application can gracefully handle unexpected errors and continue running.
7. What are streams in Node.js?
   Streams are objects that allow you to read data from a source or write data to a destination in a continuous manner. Node.js streams are particularly useful for working with large files and data, as they process data piece by piece, without loading the entire file into memory.
8. Explain the difference between require and import.
   The require statement is used in CommonJS modules, which is the module system used by Node.js. The import statement is part of the ES6 module system. While both can be used to include modules in a Node.js application, import is more modern and allows for cleaner syntax and better support for tree shaking.
9. What is the role of the V8 engine in Node.js?
   The V8 engine is the JavaScript engine developed by Google for the Chrome browser. In Node.js, the V8 engine compiles and executes JavaScript code. It provides Node.js with high performance by converting JavaScript code into machine code.
   • How can you improve the performance of a Node.js application?
     There are several ways to improve the performance of a Node.js application, including:
   • Using asynchronous programming and avoiding blocking code.
   • Optimizing database queries and using caching.
   • Leveraging cluster mode to utilize multiple CPU cores.
   • Profiling and monitoring the application to identify bottlenecks.
   • Using reverse proxies like Nginx.

• Preparing for a Node.js interview can be daunting, but being familiar with these top questions and concepts can give you a significant edge. Focus on understanding the core principles and practices, and you’ll be well on your way to acing your interview. Good luck!
• Node.js interview questions
• Asynchronous operations in Node.js
• Node.js event loop
• Node.js middleware
• Error handling in Node.js
• Node.js streams
• require vs import
• V8 engine Node.js
• Improve Node.js performance