eslint as git pre commit hook

pre-commit

#!/bin/sh
#
# An example hook script to verify what is about to be committed.
# Called by "git commit" with no arguments.  The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# To enable this hook, rename this file to "pre-commit".

if git rev-parse --verify HEAD >/dev/null 2>&1
then
    against=HEAD
else
    # Initial commit: diff against an empty tree object
    against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi

eslint=$(PATH="./node_modules/.bin:$PATH" which eslint)
if [[ -e "$eslint" ]]
then
    jsfiles=$(git diff-index --cached --name-only --diff-filter=ACM $against | grep '.js$')
    if [[ -n "$jsfiles" ]]
    then
        eslintOutput=$("$eslint" -f stylish --color -o .eslint.log $jsfiles)
        if [[ $? != 0 ]]
        then
            cat .eslint.log
            exit 1
        fi
    fi
fi

For all fans of git UIs like myself this gist may suit you better: https://gist.github.com/derlarsen/1de6f1fcd6d496e4208ff56c7eefa58d