Throughout the book we’ll be using the amazing to run code that we can edit directly in our browsers. It will look like this:

All of the code from every example in the book is also available on GitHub.

You can follow along on CodeSandbox, or, if you prefer, you can download the code and run it locally instead. However, CodeSandbox will allow us to get started with zero configuration, so if you’re not familiar with setting up a HTTP server then this will be the easiest approach.

Take a few moments to explore the CodeSandbox interface now - click “edit on CodeSandbox” above to open the example in a new window.

Working Locally


If you prefer, you can take the directory structure from the empty template and create your own local version.

The file tree

Copy the folder structure above, except for package.json and sandbox.config.json which are used to set up the Codesandbox project environment, and copy the contents of index.html and main.css into your local version. You can leave app.js empty for now.