Adding current Date as new Date() in a string key in mongo db

Question

I am trying yo add the below json to my mongo DB collection, The document has a field named value which is String.

"value" : "{\"name\"\"sample\":{\"maximumDate\":newDate(),\"is24hoursFormat\":true}}"

It is inserted correctly but when I run it, I don't get the date instead I get back new Date() as Text. I want to have current date inserted into it. Date should be always current, it is not static.

Can someone help me in this