Steps to Reproduce

run the maven command (which is part of the release script) from root of keikaicml

mvn clean process-resources -P ee -DskipTests -pl keikai
or
mvn clean process-resources -P official -DskipTests -pl keikai

Current Result

YUI compressor errors regarding newer JS language features

e.g.

[ERROR] .../target/classes/web/js/zss/ActiveRange.js:line 183:column 11:missing ; before statement
let size;

Expected Result

successful JS compression

Debug Information

seems to happen related to modern JS features

Workaround