Parsing JSON as Date (JavaScript)

Using the Http-Connector in Camunda-Modeler I want to parse a Http-Response property in form of date.

How do I archive that?
Currently I’m parsing string successfully as follows:

var json = JSON.parse(response);
json.id ?? "";

grafik

But trying to parse a date I get the following error:

grafik

org.camunda.bpm.engine.ProcessEngineException: Cannot serialize object in variable 'frist': SPIN/DOM-XML-01030 Cannot create context

How can I return the date?

Returning it as json.briefdatum it gets saved as “string”: