defineFunction

Makes function callable from scripts under name, which may be a dotted path such as app.alert: missing objects on the way are created. Arguments arrive as Kotlin values (String, Double, Boolean, List, Map or null), and the return value goes back the same way. Binary data crosses as a ByteArray: an ArrayBuffer, a typed array or a DataView arrives as a copy of the bytes it views, and a returned ByteArray reaches the script as a Uint8Array.