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

Browser compatibility

See also

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