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

Understanding JavaScript types

Before understanding the type system in TypeScript, let’s briefly explore the type system in JavaScript. To do this, open the CodeSandbox at https://codesandbox.io/ and carry out the following steps:

  1. Create a new plain JavaScript project by choosing the Vanilla option.
  2. Open index.js, remove its content, and replace it with the following code:
    let firstName = "Fred"
    console.log("firstName", firstName, typeof firstName);
    let score = 9
    console.log("score", score, typeof score);
    let date = new Date(2022, 10, 1);
    console.log("date", date, typeof date);

The code assigns three variables to various values. The code also outputs the variable values to the console, along with their JavaScript type.

Here’s the console output:

Figure 2.5 – Some JavaScript types

Figure 2.5 – Some JavaScript types

It isn’t surprising that firstName is a string and score is a number. However, it is a little...