Run JS code quality tools as precommit hook. Add in your repos ".git/hooks/" directory. Make sure file is named "precommit" (with no extension). After to add this into your hooks folder, make sure that the file has executable permissions.

pre-commit

#!/usr/bin/env python
import subprocess
import sys
import os.path, time

def get_modified_time(file):
    return time.ctime(os.path.getmtime(file))

def run_js_tools(files_str):
    """Iterate though list and run code quality tools"""
    for filename in files_str:
        # operate only on "Added" or "Modified" *.js files
        if (filename[0] == 'A' or filename[0] == 'M') and filename.endswith('.js'):
            # Get the file path
            path = filename.split('\t')[1]
            # Get original modified time
            preprocess_mtime = get_modified_time(path)
            for tool in tools:
                command = [tool, path]
                if 'beautify' in tool:
                    command.insert(1, '-r')
                proc = subprocess.Popen(command, stdout=sys.stdout)
                proc.communicate()

                # If modified time changes, we git add
                if preprocess_mtime != get_modified_time(path):
                    subprocess.Popen(['git', 'add', '-u'], stdout=sys.stdout)

                retcode = output = proc.poll()
                if retcode != 0:
                    sys.exit(tool + ' found errors, aborting commit')

if __name__ == '__main__':
    # List of preinstalled CLI tools to check through
    tools = ['js-beautify', 'jscs','jshint']
    # Get the list of staged files
    staged_files_str = subprocess.check_output(['git', 'diff', '--cached', '--name-status']).split('\n')
    # Remove newline
    staged_files_str.pop()
    run_js_tools(staged_files_str)

This doesn't give much indication of why it might fail on new dev boxes; you have to npm install -g js-beautify jscs jshint before use.

Slightly better reporting of missing tools: https://gist.github.com/scottrabin/607c4d61449766cfbced