JavaScript (Node.js) Interview: 200 Questions and Answers

The book "JavaScript (Node.js) Interview: 200 Questions and Answers" is a practical guide for developers preparing for a technical interview. It contains the most common and challenging questions asked in IT company interviews, along with detailed, structured answers with code examples.

The material covers all key topics:

• JavaScript Basics: data types, closures, prototypes, context (this), async/await, promises, Event Loop.
• Node.js: architecture, modules, streams, buffers, file system operations, clustering, error handling.
• Algorithms and Data Structures: problems on arrays, strings, trees, graphs, sorting, and searching.
• Architecture and Patterns: MVC, Singleton, Observer, Middleware, Dependency Injection.
• Testing and Debugging: unit tests, integration tests, mocks, profiling.
• Modern Technologies: TypeScript, Docker, WebSocket, REST API, GraphQL.

The book is divided into three difficulty levels:

• Junior: basic questions for beginners (50 questions).
• Middle: in-depth topics and practical tasks (100 questions).
• Senior: architectural solutions, optimization, scaling (50 questions).

Each question is accompanied not only by the correct answer but also by an explanation of why this answer is correct, as well as possible alternatives. This helps not just to memorize but to understand the logic and principles of JavaScript and Node.js.

Who this book is for:

• Junior developers preparing for their first interview.
• Middle developers looking to systematize their knowledge.
• Senior developers who want to refresh theory before an interview at a large company.
• Team leads and technical managers who conduct interviews and want to understand what questions to ask.

What you will learn:

• How to answer tricky questions about closures and prototypes.
• How to explain the Event Loop in simple terms.
• Which design patterns are most frequently asked about.
• How to solve coding problems without stress.
• How to prepare for a live-coding session.

The book is written in simple and clear language, with an emphasis on practice. All code examples can be run immediately in Node.js or a browser. This is not just a collection of questions — it is a full-fledged brain trainer for before the interview.

Perfect for self-study. Read, answer, test yourself — and go to the interview with confidence!