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

Answers

Here are the answers to the questions in the preceding section.

  1. The name prop will have the any type.
  2. The firstName state will be given the string type because string will be inferred from the initial value "".
  3. There will be no type error even though firstName is not passed because it is defined as optional.
  4. The inferred type of status is string. An explicit type can be defined for the state using a generic type argument as follows:
    const [status, setStatus] = useState<'Good' | 'Bad'>('Good');
  5. The type for the FruitList component could be as follows:
    type Props = {
      fruits: string[];
    }

Alternatively, it could be defined using an interface as follows:

interface Props {
  fruits: string[];
}
  1. The email state could be defined as follows:
    const [email, setEmail] = useState<string | null>(null);

An explicit type needs to be defined; otherwise, an initial value of null...