Checks for a real ISO 8601 date or date-time. The shape must match and the day must exist, so "2026-02-30" is rejected.
"2026-02-30"
anything
true if value is a string holding a valid ISO 8601 date
value
Checks for a real ISO 8601 date or date-time. The shape must match and the day must exist, so
"2026-02-30"is rejected.