[hooper]

If your files are under version control, you already have a generic change detection mechanism that can give you a shorter list of changed files that need to be checked for formatting. For example, you can run code formatters in pre-commit hooks. Mercurial's "fix" extension rewrites commits using formatting fixes that can be focused on changed line ranges. Of course, the purpose of this --cache feature is still valid for other situations.

[bobbylarrybobby]

In between commits, the `--cache` option is still helpful because it means you can avoid running prettier on a file whose contents have changed since the last commit but not since it was last saved.

That said, formatters should be run in pre commit hooks anyway.

[slavik81]

How do you decide what changes to restage? My experience has been that applying formatting in the pre-commit hook breaks `git add -p`.