Regex pattern for Temporal.PlainDate ISO 8601 strings (e.g. 2023-01-15).
Validates month (01–12) and day (01–31).
Also accepts the trailing [u-ca=…] annotation that toJSON() emits under a
non-ISO calendar (e.g. 2023-01-15[u-ca=hebrew]) and the signed six-digit
year form (e.g. -000753-04-21).
Regex pattern for Temporal.PlainDate ISO 8601 strings (e.g.
2023-01-15). Validates month (01–12) and day (01–31).Also accepts the trailing
[u-ca=…]annotation thattoJSON()emits under a non-ISO calendar (e.g.2023-01-15[u-ca=hebrew]) and the signed six-digit year form (e.g.-000753-04-21).