Senior Node.js Developer Interview Questions and Answers

If you're preparing for a senior Node.js developer position, it's important to be ready for technical interview questions that will test your knowledge of Node.js and its related technologies. In this article, we will provide some commonly asked interview questions and their answers to help you prepare for your upcoming interview.

Node.js Basics

Q: What is Node.js?

A: Node.js is an open-source, cross-platform, server-side JavaScript runtime environment built on the V8 engine from Google Chrome.

Q: What are the advantages of using Node.js?

A: Some of the advantages of using Node.js include:

• It's fast and efficient, thanks to its non-blocking I/O model.
• It's scalable and can handle a large number of concurrent connections.
• It allows for easy creation of RESTful APIs.
• It has a large and active community of developers.

Q: What is event-driven programming?

A: Event-driven programming is a programming paradigm in which the flow of the program is determined by events such as user input, system events, or messages from other programs or devices.

Node.js Modules

Q: What are Node.js modules?

A: Node.js modules are reusable pieces of code that can be included in a Node.js application using the require function.

Q: What is the difference between a local and a global module?

A: A local module is installed in a specific project and can only be used in that project, while a global module is installed on the system and can be used in any project.

Q: How can you create a custom Node.js module?

A: To create a custom Node.js module, you can create a new JavaScript file with your code and export the functions or objects you want to make available using the module.exports object.

Node.js Frameworks

Q: What is Express.js?

A: Express.js is a popular Node.js web framework that allows for easy creation of web applications and APIs.

Q: What is the difference between a middleware and a route handler in Express.js?

A: A middleware function is a function that sits in between the request and the response objects and can modify the request or response or perform some other action before passing control to the next middleware or route handler. A route handler is a function that handles a specific HTTP request method and path and returns a response.

Q: What is Socket.io?

A: Socket.io is a JavaScript library that enables real-time, bidirectional communication between clients and servers over web sockets.

Node.js Testing

Q: What is unit testing?

A: Unit testing is a type of testing in which individual units or components of a software application are tested in isolation from the rest of the application to ensure that they work correctly.

Q: What is Mocha?

A: Mocha is a popular JavaScript testing framework that allows for easy creation of unit tests for Node.js applications.

Q: What is Chai?

A: Chai is a JavaScript assertion library that can be used with Mocha to make test assertions in Node.js applications.

Conclusion

In conclusion, being prepared for technical interview questions is an important part of landing a senior Node.js developer position. By understanding the basics of Node.js, its modules, frameworks, and testing tools, you can demonstrate your knowledge and expertise to potential employers. As Node.js continues to grow in popularity, it's important to stay up-to-date with the latest developments and advancements in the field.