The decaffeinate tool (see #1) did not 100% convert all parts to ES6:

• there are many var statements left
• there are many older Array Methods
• lodash is often used but many of it's functions can be replaced by native ES6 counterparts
• decaffeinate added comments on the top of the files where still some unconverted things or no-op code

This issue requires #5 first to be completed in order to prevent undetected regression