I just created a basic project repository that compiles ES6 in order to use it in Codingames.
You can find it here:
Simply build the project using “npm run build” or “gulp” command lines, and either copy the content of dist/script.js in the Cogingame IDE or use the extension to watch this file locally.
Remember this is just a basic project. I know lots of you will find this obvious but I hope it will save times to some people.