Hello @bubble31,

I encounter the same exact problem for an application.

You can pass your data type and get it back via ‘properties’ argument.
The {"single_api":true} log hides a complex object.

You can access your data fields by doing the following.
const dataFields = properties.residu.listProperties()
let myData = {}
for (const f of dataFields) { myData[f] = myData.get(f)}

This schema is not complete, has JSON objects can be nested one in an other, but you can see the point.
I’ve discovered this, based on action documentation : currentUser access and methods.

I hope it will help