How to add a row to a sheet (JavaScript)

I want to create a sheet (aka table) in DT3 and add data to it using JavaScript. Creation is simple and works:

var sheet = app.createRecordWith({name: "Ausgaben " type: "sheet", columns:["A", "B", "C"] });

Adding a row, however, only gives me the error message “Error -1708: Mitteilung unverständlich.”
(Message incomprehensible). However, an empty row is added to the sheet.

Here’s what I tried:

sheet.addRow({cells: ["1","2","3"]});
app.addRow(sheet, {cells: ["1","2","3"]});
sheet.addRow({cells: {"A": "1", "B": "2", "C": "3"});
sheet.addRow( {"A": "1", "B": "2", "C": "3"});

From the output of “Events” in the Script Editor, there’s no difference between app.addRow(sheet,…) and sheet.appRow(…. However, the method call doesn’t work regardless of the kind of parameters I pass.
What is the correct way to use this method?

What does work, is this:

sheet.cells = [["1", "2","3"], ["4","5","6"]]

i.e. setting the sheet’s cell property directly to an array of arrays. However, passing an array of array as parameter to addRow still gives an error message…
Any thoughts on this method?

As noted in the Help > Documentation > Automation

I’m well aware of the preferences here. And I have my own :wink:
DT3 supports both languages, and I’d just like to know how this method has to be called from JS.

I am just saying we don’t use JavaScript internally so you’d need to wait for responses from others.