UXP: list json for document contents / structure

The screenshot is from a CEP plugin I made. With the new (beta) release of UXP scripting for InDesign we're scrapping CEP and moving to UXP

The problem now is to get a JSON object I can serialize and push to the server, i.e. the previous comment I made further up in this thread

I was hoping to be able to do something like this

<script> 
    const id = require("indesign");
    const app = id.app;  
    console.log(app.activeDocument);
    console.log(JSON.stringify(app.activeDocument));
</script>​

But I can't stringify the object, I only get this in the console

Document {}
{}

I.e. stringify doesn't work. It seems like everything in the object is functions (+ it is recursive), so I had to make a workaround that loops through the whole object up to a certain level and generate a new object.

Is there any way of getting the document as a "normal JSON object"?