For my ForeverList project, I wanted to learn how to use NSUndoManager with a list, so I spent an hour and put together a simple app demo. Check out my SimpleLists project on github. It illustrates a few basic concepts in Document-based macOS app development.
The app lets you create a simple list. You can enter new items and select existing items to delete one by one. You can save and load to a simple JSON array. As mentioned, it supports undo using NSUndoManager.
