On the future of automation generally, and more particularly on choosing between AS and JS for particular tasks, I found it encouraging to see, in the latest OmniGroup blog (
https://www.omnigroup.com/blog/looking-back-looking-ahead-2017-edition
[search for ‘JavaScript’]
) confirmation of previous indications that for the iOS as well as macOS version of their apps:
“we’re adding support for running JavaScript code: code that has the same level of deep support for manipulating the data in our apps as we’ve previously exposed to AppleScript”
It seems that this is being done by using Apple’s cross-platform JSContext technology.
https://developer.apple.com/reference/javascriptcore/jscontext
( an approach already used on macOS by HogBaySoftware’s excellent and highly scriptable TaskPaper app.