In the previous chapter we learned how to build our own Hooks by extracting custom Hooks from existing code. Then, we used our own Hooks in the blog app and learned about local Hooks and the interactions between Hooks. Finally, we learned how to write tests for Hooks using the React Hooks Testing Library, and implemented tests for our custom Hooks.

In this chapter, we are going to start by implementing a ToDo app using React class components. In the next step, we are going to learn how to migrate an existing React class component application to Hooks. Seeing the differences between function components using Hooks and class components in practice will deepen our understanding about the trade-offs of using either solution. Furthermore, by the end of this chapter we will be able to migrate existing React applications to Hooks.

The following topics will be covered in this chapter:

• Handling state with class components
• Migrating an app from class components to Hooks
• Learning about the trade-offs of class components versus Hooks