Thanks for the report @GaurangBlaze. Looks like a recent refactoring broke support for .js.es6 files in the server-side markdown cooking. We’ll get it fixed up in the next few days.
In the meantime, removing the .es6 extension from your JS files should resolve the problem. That’s a good thing to do anyway - there is no longer any need for it, and using the standard .js makes for much better IDE/editor support.