Modern Front-End Development for Rails (beta 6 pg 37) - Stimulus targets issues

I ran into issues around pg. 37 related to stimulus targets with the following console error:

day_toggle_controller.ts:6 Uncaught (in promise) TypeError: Cannot set property thingToHideTarget of # which has only a getter

I also noticed that the book src code dir stimulus/03 doesn’t work (click hide has no effect), but stimulus/04 does work. This leads me to believe the issue is related to targets but I haven’t done a thorough analysis. I’m not sure if this is likely to be versioning issues or what but it might be useful for anyone else trying to work through the book.