If I understand you correctly, you’re saying it’s an error because one did not build two apps in SwiftUI in the preceding chapter (i.e. Chapter 1), correct? If so, then yes, this would be an error, and we appreciate you pointing this out. These things do indeed happen on occasion, and we genuinely do our best to ensure that any errors or issues like this are at an absolute minimum. Having said that, we do have a forum section for every book we publish called “Errata” where you can post comments like this to bring to our attention
If you could double check this, and confirm that this is indeed the case, then please make a new post inside the “Errata” section for this book, and we will make the necessary update in a future release.