My current git pre-commit hook script for linting staged changes with ESLint

eslint-pre-commit.sh

#!/bin/bash

# if there are no staged changes, we can exit immediately
# this is fast and prevents issues when popping a stash we didn't create
STAGED_CHANGES=`git diff-index --cached HEAD --name-only --diff-filter ACMR`

if [ -z "$STAGED_CHANGES" ]; then
    exit 0
fi

git stash -q --keep-index

# Test prospective commit
git diff-index --cached HEAD --name-only --diff-filter ACMR | egrep '.js$' | xargs $(npm bin)/eslint
RESULT=$?

git stash pop -q

[ $RESULT -ne 0 ] && exit 1
exit 0