GraphQL on JavaScript (Node.js): A Complete Guide to Modern APIs

This book is a comprehensive guide to building modern, flexible, and high-performance APIs using GraphQL and Node.js. If you are tired of the limitations of REST and want to give clients (web applications, mobile applications) full control over the data they receive, then this book is for you. You will learn how to design data schemas, efficiently handle queries, solve the N+1 query problem, and build secure, scalable servers.

The book starts with the basics: what GraphQL is, how it differs from REST, and how to set up your first application on Node.js. You will get acquainted with key concepts: types and fields, queries, mutations, and subscriptions. Next, you will delve into data schema design, learning how to properly define objects, interfaces, unions, and enums.

Special attention is paid to practical aspects of development:

• Database Connectivity: integration with MongoDB, PostgreSQL, and other DBMS. Solving the N+1 problem with DataLoader.
• Authorization and Authentication: protecting fields and types, using JWT, role-based access model.
• Performance Optimization: caching, batching, query depth limiting, and query cost analysis.
• Subscriptions: adding real-time functionality using WebSocket and PubSub.
• Testing: writing unit tests for resolvers, integration testing of GraphQL queries.
• Pagination: implementing connections according to the Relay specification for efficient list loading.

The book is intended for JavaScript and Node.js developers who already have basic experience building web applications (e.g., with Express or Koa) and want to master a modern approach to building APIs. It will be useful both for beginners in GraphQL and for those who have already tried it but want to systematize their knowledge and learn about advanced techniques.

By the end of the book, you will be able to independently design and implement a full-fledged GraphQL server ready for use in a production environment. You will understand how to avoid common mistakes, how to test and document APIs, and how to integrate GraphQL with existing REST services. This is a practical guide filled with real code examples and industry best practices.

The author of the book is an experienced developer specializing in JavaScript and Node.js, with several successful GraphQL projects under their belt. Their approach is from simple to complex, with a focus on understanding rather than copying code. All examples are available for download and adapted to the latest versions of the libraries.