I'm sorry but I do not think it should.
Multiple sources say all the same, the recommended representation for a date/datetime/time in JSON is to use the ISO8601 format. JavaScript itself converts a Date type with toJSON to ISO 8601.
JSON (JavaScript Object Notation) doesn't have a built-in date type, so dates are typically represented as strings, following a standardized format.
Recommended Format: ISO 8601
The most common and widely accepted way to represent a date in JSON is:
{
"date": "2025-06-15T14:30:00Z"
}
Or see for example:
https://stackoverflow.com/questions/10286204/what-is-the-right-json-date-format
etc..
This is how the pas2js team developed the RTL TJSONDataSet (of which TWebClientDataSet descends) to use ISO8601.
If you do not include the time yourself in the JSON representation, that is what it is , you do not include it. But if you ask the dataset to generate the JSON representation, it will use ISO
8601.
I answered this already in my first reply to this post.