Prework

• Read and agree to the code of conduct and contributing guidelines.
• If there is already a relevant issue, whether open or closed, comment on the existing thread instead of posting a new issue.
• New features take time and effort to create, and they take even more effort to maintain. So if the purpose of the feature is to resolve a struggle you are encountering personally, please consider first posting a "trouble" or "other" issue so we can discuss your use case and search for existing solutions first.
• Format your code according to the tidyverse style guide.

Proposal

Check the existence of various parts of the data store:

• tar_exist_meta()
• tar_exist_objects(names)
• tar_exist_progress()
• tar_exist_process()
• tar_exist_script()

Use tar_exists_script() in tar_watch().