I would like to remove a book, its contents, its outline, and uninstall the book module itself.
I deleted all the "Book page" content type nodes. I then deleted the one book listed under: admin/structure/book
However, when I try and uninstall the module using Drush I get the message:
"To uninstall Book, delete all content that is part of a book"
I'm assuming this is the outline data on non "Book page" nodes that I missed, but there's nothing there in the Admin UI to tell me which ones they are. The UI says "No books available."
There is a module that addresses the issue of deleting book pages and their outlines in this answer here in Drupal 7.
Is there a way to easily find and delete that book content and uninstall the module in Drupal 8?