Kludgy? backup during CloudKit/CoreData development?

I am developing an iOS app (mostly for myself) where I'm entering a lot of data that would be very tedious to re-enter. Right now, my iPad works fine in CoreData, and the corresponding CloudKit database seem accurate. But I am old enough to remember when Apple decided that my nearly-empty iOS Calendar app was "the truth" and wiped out 25,000 entries on OS-X.
So, I would like a strategy for backing up the current state of either CoreData or CloudKit, in prep for trying out my app on the iPhone. If there is a way to write a file on iOS that would survive a recompile, I don't know how to do it. The only idea I have is to print() *.csv formatted records in the Xcode debugger, and cut-pasting it from Xcode to aquamacs. I'd appreciate any comments...
PS -- I haven't written JavaScript in the last decade.