https://haxe.org/
Are you using it in production? Are there any problems with it? What is the IDE support? Why is it not as popular as other languages despite the amazing cross-platform compilation/transpilation?
Haxe is in better shape than ever. The top selling steam game was written in it (Northgard). There's new vs code support that's been added recently for IDE support. Not sure about popularity... It isn't developed by a large tech company like other languages, so no fancy marketing.