Hello! This is my first post on Envato forums and I would start with a simple question: Should I use ECMAScript 6 for a new item on CodeCanyon? If yes, could be fine if I use Babel + Polyfill to convert ES6 to ES5? (just to give an old browser compatible version to the buyer).
p.s. I’m sorry for my bad English 
Slim, a product of mine, is written partly in ES6 and then converted (uncompressed and compressed versions are both contained in product package (not the original ES6 files)).
The current product I’m working on is fully written in ES6, I use Rollup (+babel plugin) to generate multiple package files for various project setups (module / commonjs / amd / global / jquery / etc.).
So I would say, go for it!
@pqina thank you for your answer. I checked out Rollup and I saw how it is powerfull. However I do not understand what do you mean with _ “to generate multiple package files for various project setups (module / commonjs / amd / global / jquery / etc.)” _, particularly for jQuery. Could you please explain?
I write it in ES6 using no dependencies.
Then I wrap the core output library in different JavaScript files based on project type. So one that translates the API to jQuerry, and one that wraps it as a AMD module, one for Angular, etc.
Thank you @pqina