Regex pattern for Temporal.PlainMonthDay ISO 8601 strings (e.g. --01-15 or 01-15).
Validates month (01–12) and day (01–31). The -- prefix is optional per ISO 8601.
Under a non-ISO calendar toJSON() emits a full reference date rather than
MM-DD (e.g. 1972-12-27[u-ca=hebrew]), so that form is accepted too — but
only with the calendar annotation present, so a bare 2023-01-15 is still
rejected.
Regex pattern for Temporal.PlainMonthDay ISO 8601 strings (e.g.
--01-15or01-15). Validates month (01–12) and day (01–31). The--prefix is optional per ISO 8601.Under a non-ISO calendar
toJSON()emits a full reference date rather thanMM-DD(e.g.1972-12-27[u-ca=hebrew]), so that form is accepted too — but only with the calendar annotation present, so a bare2023-01-15is still rejected.