Temporal.ZonedDateTime.prototype.toString()

The toString() method of {{jsxref("Temporal.ZonedDateTime")}} instances returns a string representing this date-time in the RFC 9557 format.

Syntax#

toString()
toString(options)

Parameters#

• options {{optional_inline}}
• : An object containing the following property:
  • calendarName {{optional_inline}}
  • : 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".
    • "always"
    • : Always include the calendar annotation.
    • "never"
    • : Never include the calendar annotation. This makes the returned string not recoverable to the same {{jsxref("Temporal.ZonedDateTime")}} instance, although the date value still remains the same.
    • "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.
  • fractionalSecondDigits {{optional_inline}}
  • : Either an integer from 0 to 9, or the string "auto". The default is "auto". If "auto", then trailing zeros are removed from the fractional seconds. Otherwise, the fractional part of the second component contains this many digits, padded with zeros or rounded as necessary.
  • roundingMode {{optional_inline}}
  • : A string specifying how to round off fractional second digits beyond fractionalSecondDigits. See Intl.NumberFormat(). Defaults to "trunc".
  • smallestUnit {{optional_inline}}
  • : A string specifying the smallest unit to include in the output. Possible values are "minute", "second", "millisecond", "microsecond", and "nanosecond", or their plural forms, which (except "minute") are equivalent to fractionalSecondDigits values of 0, 3, 6, 9, respectively. If specified, then fractionalSecondDigits is ignored.
  • timeZoneName {{optional_inline}}
  • : Whether to show the time zone name ([time_zone_id]) in the return value. Possible values are:
    • "auto" (default)
    • : Always include the time zone name.
    • "never"
    • : Never include the time zone name. This makes the returned string not recoverable to the same {{jsxref("Temporal.ZonedDateTime")}} instance.
    • "critical"
    • : Always include the time zone name, and add a critical flag: [!time)zone_id]. Useful when sending the string to certain systems, but not useful for Temporal itself.
  • offset {{optional_inline}}
  • : Whether to show the offset (±HH:mm) in the return value. Possible values are:
    • "auto" (default)
    • : Always include the offset.
    • "never"
    • : Never include the offset. This makes the returned string not recoverable to the same {{jsxref("Temporal.ZonedDateTime")}} instance, if the time zone is included but the time is ambiguous, or if the time zone is also not included.

Return value#

A string in the RFC 9557 format representing this date-time. The offset and calendar/time zone annotations are included as specified.

Exceptions#

• {{jsxref("RangeError")}}
• : Thrown if any of the options is invalid.
• {{jsxref("TypeError")}}
• : Thrown if options is not an object or undefined.

Examples#

Using toString()#

const zdt = Temporal.ZonedDateTime.from(
  "2021-08-01T12:34:56[America/New_York]",
);
console.log(zdt.toString()); // '2021-08-01T12:34:56-04:00[America/New_York]'

Even for the UTC time zone, the offset is +00:00, not Z:

const zdt = Temporal.ZonedDateTime.from("2021-08-01T12:34:56[UTC]");
console.log(zdt.toString()); // '2021-08-01T12:34:56+00:00[UTC]'

Using options#

For examples with rounding times, see {{jsxref("Temporal/PlainTime/toString", "Temporal.PlainTime.prototype.toString()")}}. For examples with displaying calendars, see {{jsxref("Temporal/PlainDate/toString", "Temporal.PlainDate.prototype.toString()")}}. Here we show controlling the display of time zone and offset:

const zdt = Temporal.ZonedDateTime.from(
  "2021-08-01T12:34:56[America/New_York]",
);
console.log(zdt.toString({ timeZoneName: "auto", offset: "never" })); // '2021-08-01T12:34:56[America/New_York]'
console.log(zdt.toString({ timeZoneName: "never", offset: "auto" })); // '2021-08-01T12:34:56-04:00'
console.log(zdt.toString({ timeZoneName: "never", offset: "never" })); // '2021-08-01T12:34:56'
console.log(zdt.toString({ timeZoneName: "critical", offset: "never" })); // '2021-08-01T12:34:56[!America/New_York]'

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Temporal.ZonedDateTime")}}
• {{jsxref("Temporal/ZonedDateTime/from", "Temporal.ZonedDateTime.from()")}}
• {{jsxref("Temporal/ZonedDateTime/toJSON", "Temporal.ZonedDateTime.prototype.toJSON()")}}
• {{jsxref("Temporal/ZonedDateTime/toLocaleString", "Temporal.ZonedDateTime.prototype.toLocaleString()")}}