Temporal.Duration.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.Duration instances returns a string representing this duration in the ISO 8601 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 "second", "millisecond", "microsecond", and "nanosecond", or their plural forms, which are equivalent to fractionalSecondDigits values of 0, 3, 6, 9, respectively. If specified, then fractionalSecondDigits is ignored.

Return value

A string representing the given duration in the ISO 8601 format, with subsecond components formatted according to the options. The zero duration is represented as "PT0S".

Exceptions

RangeError: Thrown if any of the options is invalid.

Examples

Using toString()

const duration = Temporal.Duration.from({ hours: 1, minutes: 30, seconds: 15 });
console.log(duration.toString()); // 'PT1H30M15S'

// Stringification implicitly calls toString()
console.log(`${duration}`); // 'PT1H30M15S'

Using options

const worldRecord = Temporal.Duration.from({ seconds: 9, milliseconds: 580 });
console.log(worldRecord.toString()); // 'PT9.58S'
console.log(worldRecord.toString({ fractionalSecondDigits: 1 })); // 'PT9.5S'
console.log(worldRecord.toString({ fractionalSecondDigits: 0 })); // 'PT9S'
console.log(worldRecord.toString({ smallestUnit: "millisecond" })); // 'PT9.580S'
console.log(
  worldRecord.toString({
    fractionalSecondDigits: 1,
    roundingMode: "halfExpand",
  }),
); // 'PT9.6S'

Specifications

Specification
Temporal proposal # sec-temporal.duration.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