Hi GS --
Now that you are Amazon, it's a bit embarrassing being the only BaaS on the internet that uses ES5:
I did some research and found out that you can enable this in 1-click on your Rhino back-end:
1. You need to call Context.setLanguageVersion to select the ES6 version or select -version 200 on the CLI.
....that's actually it. Just step 1.
* You'd have more-optimized coding
* Less support tickets. Tons of people surely try to use ES6 and wonder why it's not working. There is also more internet support (stackoverflow, etc) for ES6. All answers will be in ES6 to any questions. Less need for GS support and more self-resourceful.
* It just makes sense in 2019: You're Amazon -- Having ES5 as a cap in 2019 is sort of like seeing a website lacking SSL (https): It's shocking when it's not there.
* None: ES6 is only an extension of ES5 -- nothing went obsolete. This means you do not even have to test it! It will just naturally work.
There were so many updates promised over the past year and a half -- The only news we got were stricter limitations with no good news mixed in between with no updates. On behalf of all of your clients, please throw us a bone by adding a single param to your server-side Rhino to enable ES6 for us all.
There is only good that will come from this and with only 1 minute of labor involved, without even requiring technical knowledge to enable this. If there is just one thing you are able to do, please do this. I didn't post this in feature requests because this isn't a feature: It's a standard that should have (respectfully) been here many years ago.