Mastering Node.js by answering top interview questions

Learn UDP vs TCP and build a UDP-based notifier that broadcasts currency exchange rate updates to all connected clients using Node.js dgram.

Explore how circular dependencies occur when two modules load each other, producing an empty exports object. Learn to fix by exporting functions early and relying on hoisting for interdependent modules.

Understand how Node.js uses the event loop, call stack, and libuv thread pool to execute asynchronous code, manage callbacks in the callback queue, and prevent blocking.

Explore how micro tasks outrank macro tasks in the Node.js event loop. Compare the six event loop phases, including timers and check, and the role of promises and process.nextTick.

Learn object-oriented programming through inheritance by building a batch class that extends a product parent, initializing product name, id, and leather type via the super constructor.

Stream a large text file with the built-in http module by creating a read stream and piping it to the response in chunks.

Explore how Node.js handles CPU-heavy tasks by offloading to child processes, cluster workers, or worker threads, keeping the main thread responsive for I/O-bound workloads and multiple concurrent requests.

Explore why six crypto pbkdf2 calls run serially due to libuv’s four-thread pool, and learn to run all in parallel by increasing the thread pool size to six.

Explains session-based authentication with credentials, server-side sessions, cookies, and session IDs, and token-based authentication with JWTs stored in local storage and validated on every request.

Monolithic builds a single unit with all components, enabling easy deployment but hard scaling; microservices divide features into independent services for selective scaling and deployment.

Explore the three fundamental groups of design patterns: behavioral, creational, and structural, and see how patterns like the observer pattern, factory method, singleton, and decorator shape object communication and creation.

Explains the factory design pattern, centralizing creation of delivery objects by selecting bicycle or motor scooter based on details, via a delivery factory that instantiates the correct class.

explains the singleton pattern to ensure one shared database instance across the application by exporting an immutable singleton and reusing it everywhere.

Cache data in memory with Redis to speed Node.js responses. Learn to set up Redis with Docker, fetch data with Axios, and set TTL for cache entries.

Learn to install MongoDB for node.js development, use Compass and command-line tools, and create a Block database with a Users collection, manually or via restore.

Explore dependency injection and the service repository pattern across a three-layer architecture (controller, service, repository) using TypeScript, inversify, and express to boost testability and maintainability.

Explore serverless computing on AWS using Lambda and API Gateway to run code without server management. Learn to connect REST APIs, handle events with Lambda handlers, and deploy with stages.

Explore data structures and interview questions in node.js by calculating string length with the length property, and retrieving the fourth character using charAt(3) or bracket indexing, understanding zero-based indexing.

Demonstrate two ways to extract from E to R using slice and substring, noting zero-based indices, spaces as characters, and end-exclusive ranges.

Learn to locate the second index of a letter in text using the built-in indexOf method, starting from the first index plus one.

Learn how to use built-in string methods to lowercase, to uppercase, and trim, with practical examples on a text variable and removing leading and trailing whitespace.

Master JavaScript operator precedence and left-to-right evaluation, then reverse strings using split, reverse, and join or a for loop with slice. Explore building a regex-based email validator.