Book Image

React and React Native - Third Edition

By : Adam Boduch, Roy Derks
Book Image

React and React Native - Third Edition

By: Adam Boduch, Roy Derks

Overview of this book

React and React Native, Facebook’s innovative User Interface (UI) libraries, are designed to help you build robust cross-platform web and mobile applications. This updated third edition is improved and updated to cover the latest version of React. The book particularly focuses on the latest developments in the React ecosystem, such as modern Hook implementations, code splitting using lazy components and Suspense, user interface framework components using Material-UI, and Apollo. In terms of React Native, the book has been updated to version 0.62 and demonstrates how to apply native UI components for your existing mobile apps using NativeBase. You will begin by learning about the essential building blocks of React components. Next, you’ll progress to working with higher-level functionalities in application development, before putting this knowledge to use by developing user interface components for the web and for native platforms. In the concluding chapters, you’ll learn how to bring your application together with a robust data architecture. By the end of this book, you’ll be able to build React applications for the web and React Native applications for multiple mobile platforms.
Table of Contents (33 chapters)
Section 1: React
Section 2: React Native
Section 3: React Architecture

Cleaning up after components

In this section, you'll learn how to clean up after components. You don't have to explicitly unmount components from the DOM React handles that for you. There are some things that React doesn't know about and therefore cannot clean up for you after the component is removed.

It's for these types of cleanup tasks that the componentWillUnmount() life cycle method exists. One use case for cleaning up after React components is asynchronous code.

For example, imagine a component that issues an API call to fetch some data when the component is first mounted. Now, imagine that this component is removed from the DOM before the API response arrives.

Cleaning up asynchronous calls

If your asynchronous code tries to set the state of a component that has been unmounted, nothing will happen. A warning will be logged, and the state won't be set. It's actually very important that this warning is logged; otherwise, you would have a hard...