This seems pretty cool. I just tried using jslint to lint a file, it works! https://gist.github.com/ianjosephwilson/7c6c0a2c833e92b3a82c...
https://github.com/sqreen/PyMiniRacer/blob/master/helpers/ba...
You can easily try it once PyMiniRacer is installed to transpile JavaScript files:
cat some-file.js | python helpers/babel.py