Temporal.PlainMonthDay.prototype.toString()

The toString() method of PlainMonthDay instances returns a string representing this month-day in the RFC 9557 format.

Syntax

toString()
toString(options)

Parameters

• options Optional
  • : An object containing the following property:
    • calendarName Optional
      • : Whether to show the calendar annotation ([u-ca=calendar_id]) in the return value. Possible values are:
        • "auto" (default)
          • : Include the calendar annotation if the calendar is not "iso8601". The reference year is included if the calendar is not "iso8601".
        • "always"
          • : Always include the calendar annotation. The reference year is always included too.
        • "never"
          • : Never include the calendar annotation. This makes the returned string not recoverable to the same PlainMonthDay instance, although the month-day value still remains the same. The reference year is included if the calendar is not "iso8601".
        • "critical"
          • : Always include the calendar annotation, and add a critical flag: [!u-ca=calendar_id]. Useful when sending the string to certain systems, but not useful for Temporal itself. The reference year is always included too.

Return value

A string in the RFC 9557 format representing this month-day. The calendar annotation is included as specified. The reference year is included if a calendar annotation is included or if the calendar is not "iso8601".

Exceptions

• RangeError
  • : Thrown if any of the options is invalid.
• TypeError
  • : Thrown if options is not an object or undefined.

Examples

Using toString()

const md = Temporal.PlainMonthDay.from({ month: 8, day: 1 });
console.log(md.toString()); // '08-01'

const md2 = Temporal.PlainMonthDay.from({
  monthCode: "M08",
  day: 1,
  calendar: "chinese",
});
console.log(md2.toString()); // '1972-09-08[u-ca=chinese]'

Using options

const isoMD = Temporal.PlainMonthDay.from({ month: 8, day: 1 });
const md = Temporal.PlainMonthDay.from({
  monthCode: "M08",
  day: 1,
  calendar: "chinese",
});
console.log(isoMD.toString({ calendarName: "auto" })); // '08-01'
console.log(md.toString({ calendarName: "auto" })); // '1972-09-08[u-ca=chinese]'
console.log(isoMD.toString({ calendarName: "always" })); // '1972-08-01[u-ca=iso8601]'
console.log(md.toString({ calendarName: "always" })); // '1972-09-08[u-ca=chinese]'
console.log(isoMD.toString({ calendarName: "never" })); // '08-01'
console.log(md.toString({ calendarName: "never" })); // '1972-09-08'
console.log(isoMD.toString({ calendarName: "critical" })); // '1972-08-01[!u-ca=iso8601]'
console.log(md.toString({ calendarName: "critical" })); // '1972-09-08[!u-ca=chinese]'

Specifications

Browser compatibility

See also

• PlainMonthDay
• Temporal.PlainMonthDay.from()
• Temporal.PlainMonthDay.prototype.toJSON()
• Temporal.PlainMonthDay.prototype.toLocaleString()