Hi, I've been watching this project for quite a while(from 2017). It's good to see it is still improving.

I wonder will it support ES6+ in the future? It will be very handy.

I've done some investigation.
In qmlweb-parser. It uses gulp to copy uglifyjs 1.3.5's code to support QML. This approach makes it hard to change to new javascript parser(uglify-js3, acorn, esprima) nor can auto complete work properly. And also, it seems the AST tree is a little bit coupling with the QmlEngine and QmlBinding.