Book Image

React Design Patterns and Best Practices

By : Michele Bertoli
Book Image

React Design Patterns and Best Practices

By: Michele Bertoli

Overview of this book

Taking a complete journey through the most valuable design patterns in React, this book demonstrates how to apply design patterns and best practices in real-life situations, whether that’s for new or already existing projects. It will help you to make your applications more flexible, perform better, and easier to maintain – giving your workflow a huge boost when it comes to speed without reducing quality. We’ll begin by understanding the internals of React before gradually moving on to writing clean and maintainable code. We’ll build components that are reusable across the application, structure applications, and create forms that actually work. Then we’ll style React components and optimize them to make applications faster and more responsive. Finally, we’ll write tests effectively and you’ll learn how to contribute to React and its ecosystem. By the end of the book, you’ll be saved from a lot of trial and error and developmental headaches, and you will be on the road to becoming a React expert.
Table of Contents (19 chapters)
React Design Patterns and Best Practices
About the Author
About the Reviewer
Customer Feedback

Using indexes as a key

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

The key prop 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 props 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:

class List extends React.PureComponent 

In the constructor, the items are initialized and the handlers bound to the component:

constructor(props) {