in 2013, AIR was v3.6, now in 2019, AIR is v33.0
not only you share code via ActionScript 3 (something like TypeScript just available 10+ years ago)
but you can also develop ActionScript Native Extension (ANE) in C, C++, Objective-C, Java, C#, Swift, etc.
and it does not only publish to mobile it also publish to desktop
but that's OK, keep ignoring it
I guess it lives on here? https://github.com/apache/royale-asjs Still looks active..
Here's a demo https://royale.apache.org/tourdejewel
Adobe AIR is a compiler and a runtime
for iOS it compile AOT, for other platforms: Android, Windows, macOS, (and Linux) it compile JIT
the runtimes share the AVM2 (ActionScript Virtual Machine) and the Flash Platform API, which allow to share a lot between platforms
I agree that ActionScript was a pretty decent language to work in.
I investigated Haxe briefly but found the community wasn't very big and the community that did exist was really fragmented.
imagine if you could write command-line tools and server-side apps with it, that would be the dream