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

Questions

Answer the following questions to check what you have learned in this chapter:

  1. We have written some tests for a HomePage component and placed them in a file called HomePage.tests.tsx. However, the tests aren’t run when the npm test command is executed—not even when the a key is pressed to run all the tests. What do you think the problem might be?
  2. Why doesn’t the following expectation pass? How could this be resolved?
    expect({ name: 'Bob' }).toBe({ name: 'Bob' });
  3. Which matcher can be used to check that a variable isn’t null?
  4. Here’s an expectation that checks whether a Save button is disabled:
    expect(
      screen.getByText('Save').hasAttribute('disabled')
    ).toBe(true);

The expectation passes as expected, but is there a different matcher that can be used to simplify this?

  1. Write a test for the getNewCheckedIds function we used in this chapter. The test should check...