I migrated an Angular 8 library project to Angular 9. In my root tsconfig.json enableIvy is false. The library builds find and the unit tests pass.
When I start an app (also within the same library project) via "ng serve" I get the error "ERROR in document is not defined". However, if I set enableIvy to true for the app in tsconfig.app.json then the app starts.
How come I can't start the app with Ivy disabled?