Book Image

React Design Patterns and Best Practices. - Second Edition

Book Image

React Design Patterns and Best Practices. - Second Edition

Overview of this book

React is an adaptable JavaScript library for building complex UIs from small, detached bits called components. This book is designed to take you through the most valuable design patterns in React, helping you learn how to apply design patterns and best practices in real-life situations. You’ll get started by understanding the internals of React, in addition to covering Babel 7 and Create React App 2.0, which will help you write clean and maintainable code. To build on your skills, you will focus on concepts such as class components, stateless components, and pure components. You'll learn about new React features, such as the context API and React Hooks that will enable you to build components, which will be reusable across your applications. The book will then provide insights into the techniques of styling React components and optimizing them to make applications faster and more responsive. In the concluding chapters, you’ll discover ways to write tests more effectively and learn how to contribute to React and its ecosystem. By the end of this book, you will be equipped with the skills you need to tackle any developmental setbacks when working with React. You’ll be able to make your applications more flexible, efficient, and easy to maintain, thereby giving your workflow a boost when it comes to speed, without reducing quality.
Table of Contents (19 chapters)
Free Chapter
1
Section 1: Hello React!
4
Section 2: How React works
9
Section 3: Performance, Improvements and Production!

Using indexes as a key

In Chapter 9, Improve the Performance of Your Applications, which talks about performance and the reconciler, we saw how we can help React figure out the shortest path to update the DOM by using the key prop.

The key property uniquely identifies an element in the DOM, and React uses it to check if the element is new, or if it has to be updated when the component properties or state change.

Using keys is always a good idea and, if you don't do it, React gives a warning in the console (in development mode). However, it is not simply a matter of using a key; sometimes, the value that we decide to use as a key can make the difference. In fact, using the wrong key can give us unexpected behaviors in some instances. In this section, we will see one of those instances.

Let's, again, create a List component, as shown here:

  class List extends PureComponent...