I believe I had the exact same question a few days ago 
https://forum-next.cabbageaudio.com/t/cabbagegetvalue-in-a-k-rate-loop/2726
Btw. cabbageGetWidgetChannels works only at i-rate and retrieves an array of strings.
chngetk works on arrays though…
I’d also like to detect which element of an array changed and not only that but also detect crossing thresholds like in the trigger opcode but on arrays.