Run jshint over JavaScript files currently staged.

jshint_staged_files.py

#!/usr/bin/env python

import subprocess

"""
  Checked staged JavaScript files for jshint errors
"""
def jshint():

    errors = []

    output = subprocess.check_output(['git', 'diff-index', '--name-only', '--cached', 'HEAD'])
    js_files = [file for file in output.split('\n') if file[-2:] == 'js']

    for js_file in js_files:
      try:
       subprocess.check_output('jshint %s' % js_file, shell=True)

      except subprocess.CalledProcessError, e:
        errors.append(e.output)

    if len(errors) > 0:
      print '\n\n'.join(errors)
      print '### JSHint errors in %s files found ###\n\n' % len(errors)
    else:
      print '\nNo JSHint errors found. You\'re awesome!\n'


if __name__ == '__main__':
    jshint()