A Friday afternoon (my time) gift for @tmetzke:

What is the purpose of the change

Updates the pre-commit hook to run prettier against only files that have changed, for much faster commits.

How?

I was using lint-staged incorrectly! In a case of over-pursuing the DRY principle, I configured lint-staged to run npm run format, to avoid defining what "format" meant in two places.

But the format script passes . as the path to prettier, resulting in the entire codebase being formatted even for a one line change.

lint-staged passes a glob for the committed files to the configured command...this change takes advantage of that, and now the hook will only format the files being committed.

Before this change

After this change

PR Checklist

• My changes apply to an already released version, and I have added them to the relevant /versioned_docs directory, or they are not for an already released version.
• My changes apply to future versions, and I have added them to the main /docs directory, or they are not for future versions.
• My changes require an Engineering review, and I've assigned an engineering manager or tech lead as a reviewer, or my changes do not require an Engineering review.
• My changes require a technical writer review, and I've assigned @christinaausley as a reviewer, or my changes do not require a technical writer review.