It looks like the callback function is passed a string as its only argument, combining the property and the value separated with a comma.
This seems very odd to me. Why is it like that and not a callback with 2 arguments? If you want to act on the values you first have to parse the thing...?
Here are my findings. If you just print it it looks like 2 values because the post function interprets the comma, but if you print the type of the argument or convert the js arguments object to string you see that its actually an object:
This is my callback:
post("Live api path/property change:", v, "n");
post("type", typeof v, "n");
post("argments", argumentsToString(arguments), "n");
I created the argumentsToString function to concat js function arguments into a string:
// convert arguments object to real array
var args = Array.prototype.slice.call(v);
var str = args.join(" ");
This is the output in the max window:
Live api path/property change: playing_slot_index 3
I don't know what to think of that, but it seems at least a little weird.