Date recognition and picker

[AlexRMU]

Timestamp recognition is already available (https://github.com/josdejong/svelte-jsoneditor/issues/106), you can add date recognition. And add a date picker to both.

• memorize the original/received value
• don't recognize long strings

[AlexRMU]

Such requests depend on personal preferences. They could be solved through plugins or a more flexible api.

[josdejong]

That makes sense.

We can start a collection of extra value render components, like discussed here: https://github.com/josdejong/svelte-jsoneditor/issues/375#issuecomment-1867366360