ES 6 Summary
- modules
- module loaders
- classes
- subclassable built-ins
- symbols
- arrows
- enhanced object literals
- template strings
- destructuring
- default + rest + spread
- let + const
- iterators + for..of
- generators
- promises
- tail calls
- unicode
- map + set + weakmap + weakset
- math + number + string + array + object APIs
- binary and octal literals
- reflect api
- proxies
