git hook for pre-commit to use ESLint and flake8 as a soft guard of code quality (lets things pass if the committer is committed to committing)

pre-commit

#!/bin/bash

# Uses ESLint as a soft guard of code quality for your repo
# allows commits to go through if re-attempted within a pre-set interval
# copy to .git/hooks/commit-msg to have things work

# Based on: https://gist.github.com/wesbos/8aec9d2ff7f7cf9dd65ca2c20d5dfc23

PRESET_TIME_INTERVAL=20

LAST_RUN_DATE_FILE="$HOME/.eslint.commit-msg-hook.last-failed-run"
if [ ! -f $LAST_RUN_DATE_FILE ] ; then
    echo "0" > $LAST_RUN_DATE_FILE
fi

# because somehow /usr/local/bin might not be on the path
PATH=$PATH:/usr/local/bin:/usr/local/sbin

CURR_EPOCH=$(date +%s)
LAST_RUN_EPOCH=$(cat $LAST_RUN_DATE_FILE)
TIME_DIFFERENCE_IN_SEC=$(expr $CURR_EPOCH - $LAST_RUN_EPOCH)

function eslint_js {
  files=$(git diff --cached --name-only | grep -E '(.js|.jsx)$')

  eslint_failed=0
  # Prevent ESLint help message if no files matched
  if [[ $files != "" ]] ; then
    for file in ${files}; do
      git show :$file | eslint $file
      if [[ $? != 0 ]] ; then
        eslint_failed=1
      fi
    done;
  fi
}


function flake8_py {
  files=$(git diff --cached --name-only | grep '\.py\?$')

  flake8_failed=0
  # Prevent ESLint help message if no files matched
  if [[ $files != "" ]] ; then
    for file in ${files}; do
      git show :$file | flake8 $file
      if [[ $? != 0 ]] ; then
        flake8_failed=1
      fi
    done;
  fi
}

flake8_py;
eslint_js;

if [[ eslint_failed -gt 0 || flake8_failed -gt 0 ]] ; then
  failed=1
else
  failed=0
fi

if [[ $failed != 0 ]] ; then
  echo "💩 💩 💩 ESLint or flake8 failed."
  if [ "$TIME_DIFFERENCE_IN_SEC" -ge $PRESET_TIME_INTERVAL ]; then
    echo "🚫 🚫 🚫 git commit denied!"
    echo "Attempt to commit again within $PRESET_TIME_INTERVAL seconds and the commit will succeed.";
    echo "... and please ensure that there are no syntax errors if you do so.";
    date +%s > $LAST_RUN_DATE_FILE
    exit $failed
  else
    echo "Current commit attempt is within $PRESET_TIME_INTERVAL seconds of last failed attempt.";
    echo "😡 😡 😡 git commit reluctantly allowed.";
      echo "0" > $LAST_RUN_DATE_FILE
  fi
fi