This is using Jest v24 not v23.

From the create command:

        scripts: {
          start: 'tsdx watch',
          build: 'tsdx build',
          test: template === 'react' ? 'tsdx test --env=jsdom' : 'tsdx test',

So it's wasn't necessary to say

If you are trying to test a React component, you likely want to pass in --env=jsdom just like you do in Create React App

Proposed:

If you are using the React template, jest uses the flag --env=jsdom by default.