Temporal.PlainDateTime.prototype.toString()

Limited availability

This feature is not Baseline because it does not work in some of the most widely-used browsers.

Experimental: This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

The toString() method of Temporal.PlainDateTime instances returns a string representing this date-time in the RFC 9557 format.

Syntax

js
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".

"always"

Always include the calendar annotation.

"never"

Never include the calendar annotation. This makes the returned string not recoverable to the same Temporal.PlainDateTime 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

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

A string specifying how to round off fractional second digits beyond fractionalSecondDigits. See Intl.NumberFormat(). Defaults to "trunc".

smallestUnit Optional

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.

Return value

A string in the RFC 9557 format representing this date-time. The calendar annotation is included as specified.

Exceptions

RangeError

Thrown if any of the options is invalid.

TypeError

Thrown if options is not an object or undefined.

Examples

Using toString()

js
const dt = Temporal.PlainDateTime.from("2021-08-01T12:34:56");
console.log(dt.toString()); // '2021-08-01T12:34:56'

For examples with rounding times, see Temporal.PlainTime.prototype.toString(). For examples with displaying calendars, see Temporal.PlainDate.prototype.toString().

Specifications

Specification
Temporal proposal
# sec-temporal.plaindatetime.prototype.tostring

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
toString
Experimental

Legend

Tip: you can click/tap on a cell for more information.

No support
No support
Experimental. Expect behavior to change in the future.
See implementation notes.
User must explicitly enable this feature.

See also