I've just started learning Arcade and I am having an issue with something that I assumed would be so simple. I am trying to use a custom expression on label features to show "ASMT" when "Situs.Addr" is empty. Here's what I have, but it fails to show "ASMT" when "Situs.Addr" is empty.
IIf(IsEmpty($feature["Situs_Addr"]), $feature.ASMT, $feature["Situs_Addr"])
I know the syntax switches in arcade to reference attributes (also not sure why - anyone?), so you may need $feature["ASMT"] along the lines of the other attributes you have.