Git hook to lint (eslint) and format (prettier) staged files and abort the commit if anything has changed.

package.json

{
  "scripts": {
    "prepare": "test -f .git/hooks/pre-commit || cp scripts/pre-commit .git/hooks",
    "format": "prettier . --cache",
    "lint": "eslint . --report-unused-disable-directives --max-warnings 0 --cache",
  }
}

pre-commit

#!/usr/bin/env sh

set -ue

# shellcheck disable=SC2046
md5sum $(git diff --diff-filter=ACMR --cached --name-only | xargs) > /tmp/pre-commit-summary

echo "---> Checking code… ⚠️" >&2

(
	npm run-script --silent format -- --write
	npm run-script --silent lint -- --fix
) >/dev/null 2>&1 || :

if ! md5sum --status --check /tmp/pre-commit-summary; then
	echo "---> The pre-commit hook has changed some of the files being commited. Please review these changes and try again. ❌" >&2
	exit 1
fi

echo "---> All good. ✅" >&2