Temporal.PlainYearMonth.prototype.toString()

The toString() method of PlainYearMonth instances returns a string representing this year-month 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 day is included if the calendar is not "iso8601".
        • "always"
          • : Always include the calendar annotation. The reference day is always included too.
        • "never"
          • : Never include the calendar annotation. This makes the returned string not recoverable to the same PlainYearMonth instance, although the year-month value still remains the same. The reference day 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 day is always included too.

Return value

A string in the RFC 9557 format representing this year-month. The calendar annotation is included as specified. The reference day 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 ym = Temporal.PlainYearMonth.from({ year: 2021, month: 8 });
console.log(ym.toString()); // '2021-08'

const ym2 = Temporal.PlainYearMonth.from({
  year: 5781,
  monthCode: "M08",
  calendar: "hebrew",
});
console.log(ym2.toString()); // '2021-04-13[u-ca=hebrew]'

Using options

const isoYM = Temporal.PlainYearMonth.from({ year: 2021, month: 8 });
const ym = Temporal.PlainYearMonth.from({
  year: 5781,
  monthCode: "M08",
  calendar: "hebrew",
});
console.log(isoYM.toString({ calendarName: "auto" })); // '2021-08'
console.log(ym.toString({ calendarName: "auto" })); // '2021-04-13[u-ca=hebrew]'
console.log(isoYM.toString({ calendarName: "always" })); // '2021-08-01[u-ca=iso8601]'
console.log(ym.toString({ calendarName: "always" })); // '2021-04-13[u-ca=hebrew]'
console.log(isoYM.toString({ calendarName: "never" })); // '2021-08'
console.log(ym.toString({ calendarName: "never" })); // '2021-04-13'
console.log(isoYM.toString({ calendarName: "critical" })); // '2021-08-01[!u-ca=iso8601]'
console.log(ym.toString({ calendarName: "critical" })); // '2021-04-13[!u-ca=hebrew]'

Specifications

Browser compatibility

See also

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