I have used Prettier to format code samples, and its configuration is set within package.json in each of the appointments and spec-logo projects. Here it is:

"prettier": {
  "singleQuote": true,
  "printWidth": 67,
  "jsxBracketSameLine": true
}

Feel free to change this to your own configuration and reformat files as you see fit. The line width of 67 characters is particularly short but ensures that, for the most part, code snippets do not suffer from line breaks.

The one place this is not true is with test descriptions:

it('passes from and to times through to appointments when retrieving appointments', async () => {

In these cases, although the text is printed over two lines, you should enter it on one line only. If you are copy and pasting code samples from the electronic version of this book, you’ll need to remove the extra line breaks that are inserted by your editor.