Doesn't run in browser without the "modules: 'commonjs'" setting

[screenm0nkey]

The compiled ES5 code doesn't run in a browser when the modules property is not on the grunt task. So it works fine with "modules: 'commonjs'", but doesn't without it and it's because the compiled JS is missing 'System.get()' call at the bottom of the compiled JS i.e.

System.get("src/es6/inheritance.js" + '');

[screenm0nkey]

Also there is an issue with the source maps. I'm not sure what it is. It generates the maps ok but Chrome Dev tools doesn't recognise them.