Format JS and JSX code with `prettier-standard` on commit

pre-commit

#!/bin/sh
#
# A hook script to format JS and JSX files wth 'prettier-standard'.
# Called by "git commit" with no arguments.
#
# If formatting causes an empty commit, the commit will abort (`exit 1`).
#
# FAQ
# ====
#
# It's not running?!
# =====
# Try running `chmod +x .git/hooks/pre-commit`
#
# Changes are still in Git after the commit..
# =====
# See for a potential `post-commit` fix: https://github.com/prettier/prettier/issues/2978#issuecomment-354982956
#

STAGED_JS_FILES=$(git diff --cached --name-only --diff-filter=ACM "*.js" "*.jsx" | tr '\n' ' ')

# Don't run format code if there are no .js[x] files to format..
if [[ "$STAGED_JS_FILES" = "" ]]; then
  exit 0
fi

echo "\nFormatting Javascript:\n"

# Check for prettier-standard
which ./node_modules/.bin/prettier-standard &> /dev/null
if [[ "$?" == 1 ]]; then
  echo "\t\033[41mPrettier not setup on Project\033[0m"
  exit 0
else
  # Prettify all staged .js[x] files
  echo "$STAGED_JS_FILES" | xargs ./node_modules/.bin/prettier-standard

  # Add back the modified/prettified files to staging
  echo "$STAGED_JS_FILES" | xargs git add

  # Check to see if any files staged
  # Abort if we zero staged files after formatting (empty commit)
  if [[ $(git diff --cached --name-only | tr '\n' ' ') = "" ]]; then
    echo "\nNo longer files staged, aborting commit.\n"
    exit 1
  fi
fi

# 🚀
exit 0