400+ Node JS Interview Questions Practice Test [2023]

Gain insights into Node JS global objects, JSON integration, npm, and the essentials of buffers and streams.

These fundamental concepts are the backbone of Node JS and are often central to interview questions.

Learn about Stream API, Process and OS Modules, and delve into the complexities of Crypto and Child Processes.

These topics are not just crucial for interviews but also for practical Node JS application development.

Engage with security best practices, server-side rendering, and microservices, ensuring you're ready for high-level interview questions.

Understand memory leak handling and native addons, enhancing your Node JS expertise.

Compare Sails.js with real-time applications, and understand GraphQL and Socket io integration.

Get acquainted with testing frameworks and templating engines, a must-know for advanced Node JS interviews.

Delve into event emitters, asynchronous error handling, and stream-based processing.

Learn about async hooks and the event loop, crucial for any Node JS developer.

Understand the nuances of load balancing, environment configurations, and scaling Node JS applications.

Learn about profiling and deploying Node JS applications on cloud platforms, a sought-after skill in the industry.

B) To manage Node JS project dependencies

C) To create new Node JS projects

D) To optimize Node JS applications for performance

Answer: B) To manage Node JS project dependencies

Explanation: npm is an integral part of Node JS, primarily used for managing project dependencies. It allows developers to install, update, and manage libraries and packages that a project requires. This is crucial in modern development, where leveraging existing packages for functionality is a common practice, reducing development time and increasing efficiency.

Question: In Node JS, how are 'Buffers' primarily used?

B) For handling streaming data

C) For storing user session data

D) For managing environment variables

Answer: B) For handling streaming data

Explanation: Buffers are used in Node JS to handle binary data while performing operations like reading from or writing to files, interacting with streams, or handling TCP streams. In scenarios where dealing with large volumes of data is common, buffers play a vital role in efficiently handling this data in chunks, ensuring better performance and resource management.

Question: Which feature of Node JS aids in executing non-blocking operations?

B) Callback Queue

C) Child Processes

D) Global Scope

Answer: A) Event Loop

Explanation: The Event Loop is a fundamental aspect of Node JS that allows non-blocking operations. It handles asynchronous callbacks and is a pivotal part of the Node JS runtime environment. The Event Loop works by polling for events and executing the callbacks associated with these events, thus facilitating a non-blocking, event-driven architecture that is central to Node JS's performance efficiency.

Question: What does Express.js primarily provide for Node JS applications?

B) A robust plugin system

C) A server-side web application framework

D) Enhanced security features

Answer: C) A server-side web application framework

Explanation: Express.js is a popular server-side web application framework for Node JS. It simplifies the development of web applications and APIs by providing a range of features like simplified routing, middleware support, and template engine integration. This makes developing complex applications and services more manageable, allowing developers to focus on application logic rather than the intricacies of underlying HTTP protocols and processes.

Question: In Node JS, what is the primary purpose of using middleware in Express.js?

B) To handle HTTP requests and responses

C) To connect to various databases

D) To encrypt sensitive data

Answer: B) To handle HTTP requests and responses

Explanation: Middleware functions in Express.js are fundamentally used to process HTTP requests and responses. They can modify request and response objects, end the request-response cycle, and call the next middleware in the stack. This is crucial for tasks like parsing request bodies, adding response headers, authenticating requests, and logging request details. Middleware provides a flexible way to perform these operations, allowing developers to create modular and reusable code.