Is ActionScript still a thing on Macs? I feel like that tech was almost criminally overlooked while being the backbone for a lot of processing pipelines back in the day.
The documentation is the Objective-C docs, I use those all the time. You do need to understand the basics of how to translate from the Objective-C APIs to what JXA (or AppleScript) expects, but once it clicks you can do it for essentially anything with the same logic.