safely-bump-deps.sh does not need to do impossibly hard things. It can just call npm: outdated, install --save-exact and/or install --package-lock-only. There's plenty of solutions here.
Pushing this into a hook makes it invisible, implicit, hard to debug, and an entry point for all sorts of undefined behaviours.
Pushing this into a hook makes it invisible, implicit, hard to debug, and an entry point for all sorts of undefined behaviours.