@screnshaw, last suiteworld they demoed some enhancements to suitescript 2.x including allowing for ES6 classes and let/const ect. They said it would be released q1/q2 2019. It was probably an accidental early release of that stuff. My best guess at least.

Sounds about right since it was up for such a short time. Thanks!

this would be awesome - it would make TS sources look very similar to the JS output. I've been using the ES2015 features for a years now (via TypeScript) so having it native can't come too soon!