React: Up & Running, 2nd Edition

Chapter 1. Hello World

Let’s get started on the journey to mastering application development using React. In this chapter, you will learn how to set up React and write your first “Hello World” web app.

Setup

First things first: you need to get a copy of the React library. There are various ways to go about it. Let’s go with the simplest one that doesn’t require any special tools and can get you learning and hacking away in no time.

Create a folder for all the code in the book in a location where you’ll be able to find it.

For example:

$ mkdir ~/reactbook

Create a /react folder to keep the React library code separate.

$ mkdir ~/reactbook/react

Next, you need to add two files: one is React itself, the other is the ReactDOM add-on. You can grab the latest 17.* versions of the two from the unpkg.com host, like so:

$ curl -L https://unpkg.com/react@17/umd/react.development.js > ~/reactbook/react/react.js
$ curl -L https://unpkg.com/react-dom@17/umd/react-dom.development.js > ~/reactbook/react/react-dom.js

Note that React doesn’t impose any directory structure; you’re free to move to a different directory or rename react.js however you see fit.

You don’t have to download the libraries; you can use them directly from unpkg.com. However, having them locally makes it possible to learn anywhere and without an internet connection.

Note

The @17 in the URLs shown in the preceding example gets you a copy of the latest React 17, which is current at the time of writing this book. Omit