I wanted to always have up to date hash of contents of the directory after any change to use as a cache key. Started to list files, hashing them only to realize jj is already constantly doing that 😬
$ jj log --limit 1 -r "ancestors(@)" -T "self.commit_id()" --no-graph src/
# git hash
$ jj log --limit 1 -r "ancestors(@)" -T "self.commit_id().short()" --no-graph src/
# short hash