Temporal.PlainTime.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.PlainTime instances returns a string representing this time in the RFC 9557 format.

Syntax

toString()
toString(options)

Parameters

options Optional

An object containing some or all of the following properties (in the order they are retrieved and validated):

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 time.

Exceptions

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

Examples

Using toString()

const time = Temporal.PlainTime.from("12:34:56");
console.log(time.toString()); // '12:34:56'

Using options

const time1 = Temporal.PlainTime.from("12:00:00");
console.log(time1.toString()); // '12:00:00'
console.log(time1.toString({ fractionalSecondDigits: 1 })); // '12:00:00.0'
console.log(time1.toString({ smallestUnit: "minute" })); // '12:00'
console.log(time1.toString({ smallestUnit: "nanosecond" })); // '12:00:00.000000000'

const time2 = Temporal.PlainTime.from("12:34:56.123456789");
console.log(time2.toString({ fractionalSecondDigits: 4 })); // '12:34:56.1234'
console.log(
  time2.toString({ fractionalSecondDigits: 4, roundingMode: "halfExpand" }),
); // '12:34:56.1235'

Specifications

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

Browser compatibility

	Desktop					Mobile						Server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android	Deno	Node.js
`toString`	No	No	No	No	preview	No	No	No	No	No	No	1.40	No