Book Image

Learn React with TypeScript - Second Edition

By : Carl Rippon
4.4 (8)
Book Image

Learn React with TypeScript - Second Edition

4.4 (8)
By: Carl Rippon

Overview of this book

Reading, navigating, and debugging a large frontend codebase is a major issue faced by frontend developers. This book is designed to help web developers like you learn about ReactJS and TypeScript, both of which power large-scale apps for many organizations. This second edition of Learn React with TypeScript is updated, enhanced, and improved to cover new features of React 18 including hooks, state management libraries, and features of TypeScript 4. The book will enable you to create well-structured and reusable React components that are easy to read and maintain, leveraging modern design patterns. You’ll be able to ensure that all your components are type-safe, making the most of TypeScript features, including some advanced types. You’ll also learn how to manage complex states using Redux and how to interact with a GraphQL web API. Finally, you’ll discover how to write robust unit tests for React components using Jest. By the end of the book, you’ll be well-equipped to use both React and TypeScript.
Table of Contents (19 chapters)
1
Part 1: Introduction
6
Part 2: App Fundamentals
10
Part 3: Data
14
Part 4: Advanced React

Using the ref Hook

In this section, we will learn about the ref Hook and where it is useful. We will then walk through a common use case of the ref Hook by enhancing the PersonScore component we have been working on.

Understanding the ref Hook

The ref Hook is called useRef and it returns a variable whose value is persisted for the lifetime of a component. This means that the variable doesn’t lose its value when a component re-renders.

The value returned from the ref Hook is often referred to as a ref. The ref can be changed without causing a re-render.

Here’s the syntax for useRef:

const ref = useRef(initialValue);

An initial value can optionally be passed into useRef. The type of the ref can be explicitly defined in a generic argument for useRef:

const ref = useRef<Ref>(initialValue);

The generic argument is useful when no initial value is passed or is null. This is because TypeScript won’t be able to infer the type correctly.

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