JavaScript (Node.js) Application Architecture

The book "JavaScript (Node.js) Application Architecture" is a practical guide for developers who want to go beyond simple scripts and learn how to design complex, scalable, and maintainable server-side systems on Node.js. The author, Alexey Sokolov, shares years of experience building high-load projects, from organizing code in a monolith to implementing a microservice architecture.

What is this book about?

The book covers the full cycle of designing backend applications on Node.js. You will learn:

• Layered architecture: how to split an application into controllers, services, repositories, and middlewares to keep code clean and testable.
• Design patterns: Dependency Injection, Repository, Observer, Middleware, and other patterns in the context of Node.js.
• Working with databases: designing repositories, working with ORMs (Sequelize, TypeORM), and query optimization.
• Microservices: splitting a monolith, inter-service communication (REST, gRPC, message brokers), managing transactions and data consistency.
• Scaling: clustering, load balancing, caching (Redis), queues (Bull, RabbitMQ), and handling large volumes of data.
• Testing: unit tests, integration tests, API testing, and E2E tests using Jest, Mocha, and Supertest.

Who is this book for?

The book is intended for:

• JavaScript developers with at least 1 year of experience with Node.js who want to deepen their knowledge of architecture.
• Backend developers transitioning from other languages (Python, PHP, Java) to Node.js.
• Team leads and architects looking for proven approaches to designing server applications.
• Developers facing challenges with maintaining and scaling existing projects.

What will you learn?

• How to avoid "spaghetti code" and build a modular architecture.
• How to properly organize error handling and logging.
• How to design an API that is easy to extend and document.
• How to transition from a monolith to microservices without downtime or data loss.
• How to test architectural decisions and refactor code without fear.

The book contains many real-world code examples, diagrams, and checklists. After reading it, you will be able to confidently design systems that can withstand high loads and easily adapt to new business requirements.