React Anti-Patterns

Build efficient and maintainable React applications with test-driven development and refactoring

Building frontend applications is challenging, especially when constructing large ones, and the difficulty escalates without proper guidance. Unfortunately, many React-based applications fall into this scenario due to the library’s UI-centric nature, leaving developers to navigate the other complexities of frontend development on their own. There are numerous other considerations such as asynchronous network requests, accessibility, performance, and state management, to name a few. These factors contribute to the complexity of frontend applications. As the scale of the application grows, maintaining the code becomes an arduous task. Adding new features requires considerably more time than it first appears, and identifying defects (and then fixing them) is equally challenging, if not more so.

However, these challenges are surmountable. We can learn to identify common anti-patterns that cause problems, then employ established patterns, design principles, and practices to address and rectify these issues. History teaches us that solutions derived in one field often find relevance in others, especially when it comes to fundamental design principles such as the Single Responsibility Principle, the Dependency Inversion Principle, and Don’t Repeat Yourself. These principles guided the construction of UNIX systems back in the 1970s and Java Swing applications in the 1990s, and they remain valid today. They will undoubtedly continue to be pertinent for future frameworks and libraries.

I've explored these themes in a number of articles and books. Two of my most recent works, Modularizing React Applications with Established UI Patterns and Headless Component: a pattern for composing React UIs, delve into these concepts in depth. Additionally, the second edition of my book, Test-Driven Development with React and TypeScript, is a further exploration into crafting code that excels in maintainability and clarity.

The book delves into numerous well-established patterns, ranging from the renowned S.O.L.I.D principles to the Anti-Corruption Layer (ACL), and from the art of Composition to the intricacies of Data Modeling.

I am convinced that synthesizing these frequent examples and the code we encounter daily to confront their inherent challenges—and to provide actionable solutions—is highly beneficial. This book represents the essence of such an endeavor.

This book seeks to delve into these problems and examine how established patterns and practices can mitigate the challenges of building large applications. We’ll see how design principles and design patterns can simplify the design, making the code easier to understand, modify, and maintain in the long run. Through this exploration, readers will gain a deeper understanding of how to navigate the multifaceted world of frontend development with React, ensuring their applications are both robust and maintainable.

Who this book is for

This book is for React developers who are interested in improving the maintainability and efficiency of their code. Whether you’re just starting out or have some experience under your belt, there’s something here for you. It’s beneficial to have a basic understanding of React, but the book aims to guide you through the concepts in a straightforward manner.

The focus is on identifying common anti-patterns and addressing them with established design principles and patterns. Through practical examples and a step-by-step approach, you’ll learn how to simplify your code for better understanding, easier modifications, and long-term maintenance.

What this book covers

In Chapter 1, Introducing React Anti-Patterns, you’ll get a closer look at the hurdles of building user interfaces, handling state management, addressing “unhappy paths,” and identifying common anti-patterns in React.

In Chapter 2, Understanding React Essentials, you will delve into the basics of React covering static components, props, UI breakdown, state management, the rendering process, and common React Hooks to lay a solid foundation for subsequent chapters.

In Chapter 3, Organizing Your React Application, you will learn about different types of project structures in React, exploring their advantages, drawbacks, and practical applications.

In Chapter 4, Designing your React Components, you will learn to identify common anti-patterns in React component design and explore fundamental design principles including the Single Responsibility Principle and Don’t Repeat Yourself to improve component structure.

In Chapter 5, Testing in React, you will learn about the significance of software testing, explore various types of tests such as unit, integration, and end-to-end testing, and get acquainted with popular testing tools including Cypress and Jest, setting a strong foundation for complex testing scenarios in React applications.

In Chapter 6, Exploring Common Refactoring Techniques, you will learn about the essence of refactoring and delve into various refactoring techniques, such as Rename Variable, Extract Variable, and Replace Loop with Pipeline, to enhance code maintainability and readability.

In Chapter 7, Introducing Test-Driven Development with React, you’ll learn the core principles of Test- Driven Development (TDD) through a practical example, while building various features of a pizza store’s menu page in a React application.

In Chapter 8, Exploring Data Management in React, you’ll delve into the common challenges of state management in React, such as business logic leaks and prop drilling, and explore solutions including employing an Anti-Corruption Layer and utilizing the React context API to enhance code maintainability and user experience.

In Chapter 9, Applying Design Principles in React, you’ll revisit the Single Responsibility Principle, embrace the Dependency Inversion Principle, and understand the application of CQRS in React to fortify your knowledge of key design principles to aid you in mastering React.

In Chapter 10, Diving Deep into Composition Patterns, you’ll delve into composition through higher- order components and custom Hooks, and explore the headless component pattern. You’ll gain an appreciation of composition techniques for creating scalable, maintainable, and user-friendly UIs in React.

In Chapter 11, Introducing Layered Architecture in React, you’ll explore Layered Architecture, delve into Application Concern Layers, define data models, and learn strategy patterns through a practical example, understanding their significance for large-scale applications.

In Chapter 12, Implementing an End-To-End Project, you’ll traverse the complete process of developing a weather application, from understanding requirements to implementing features such as City Search and Add To Favourite, while ensuring the code remains maintainable, understandable, and extensible.

In Chapter 13, Recapping Anti-Pattern Principles, we’ll take a concise look back at common anti- patterns, React design patterns, and fundamental principles, and recap the techniques and practices discussed earlier in the book, providing a succinct refresher before you continue applying these insights to your own projects.

About the author

Juntao Qiu is an accomplished software developer with over 15 years of industry experience, dedicated to helping others write better code. With a strong passion for crafting maintainable and high-quality code, he has become a trusted resource in the industry. As an author, Juntao has shared his expertise through influential books such as Maintainable React (2022) and Test-Driven Development with React and TypeScript – Second Edition (2023).

He orchestrates a blend of code snippets, illustrations, and before and after comparisons to unravel intricate concepts, making them accessible to fellow developers. His insightful blog posts at I Code It newsletter and educational videos on YouTube are a testament to his commitment to sharing knowledge and fostering a deeper understanding of coding practices within the developer community.