isValidCalendarDate

Signature

isValidCalendarDate(value: string): boolean

Return true if value is a valid GMT PlainDate string: a bare ISO date (“2024-10-03”) or an RFC 9557 calendar-annotated date (“2024-10-03[u-ca=hebrew]”), as Temporal.PlainDate#toString() and convertDateToCalendar write it.

• The digits are the ISO date whatever the calendar, so the ISO date must be valid and within Temporal’s range (-271821-04-19 to +275760-09-13). The year is four digits or a sign and six.
• A [u-ca=<id>] annotation, optionally critical ([!u-ca=hebrew]). Temporal’s CanonicalizeCalendar validates the id, folding case and aliases ([u-ca=HEBREW], [u-ca=ethiopic-amete-alem]), and the calendar must be one GMT supports (CalendarSystem); chinese, dangi, islamic and islamic-rgsa return false.
• The annotations follow Temporal’s ISO grammar, as Temporal.PlainDate.from reads them: a time zone annotation and elective unknown annotations ([foo=bar]) are ignored and the first u-ca annotation names the calendar; an unknown critical annotation ([!foo=bar]) or a second u-ca annotation when either is critical returns false.
• A date-time is valid and names its date, as Temporal.PlainDate.from reads it ("2024-10-03T14:30[u-ca=hebrew]" is 2024-10-03 in Hebrew): the time is dropped.
• The part before the first [ must match GMT’s strict extended shape, as isValidDate and isValidDateTime require: basic format (20241003), a space or lower-case t separator, a UTC offset or designator and a leap second (second 60) return false, although Temporal.PlainDate.from reads all but the designator.
• Returns false for non-strings or empty strings. Compatibility: since 1.16.0 the string is RFC 9557, and a date-time is read as its date (earlier releases returned false). Earlier releases accepted calendar-native digits, ;era= and the ids gregorian, taiwan, islamic-tabular and ethiopic-amete-alem; a ;era= string or a six-digit unsigned year now returns false, and any other such string is read as the ISO date its digits spell.

Parameters

Parameter	Type	Description
value	string	ISO PlainDate string, optionally calendar-annotated

Returns

boolean indicating validity

Examples

import { isValidCalendarDate } from "@northguild/gmt/plain/validate";

isValidCalendarDate("2024-10-03") // true

value

output

 

Source

plain/validate/isValidCalendarDate.ts