Temporal.PlainTime.prototype.add() - JavaScript | MDN

Syntax

Parameters

duration

A string, an object, or a Temporal.Duration instance representing a duration to add to this time. It is converted to a Temporal.Duration object using the same algorithm as Temporal.Duration.from().

Return value

A new Temporal.PlainTime object representing the time specified by the original PlainTime, plus the duration. Any units above hours are ignored, and if the time goes past midnight, it wraps around to the next day.

Adding a duration is equivalent to subtracting its negation.

Examples

Adding a duration

js

const start = Temporal.PlainTime.from("12:34:56");
const end = start.add({ hours: 1, minutes: 30 });
console.log(end.toString()); // 14:04:56

const end2 = start.add({ hours: -1, minutes: -30 });
console.log(end2.toString()); // 11:04:56

const distance = Temporal.PlainTime.from("00:00:00").until("01:23:45"); // 1h 23m 45s
const end3 = start.add(distance);
console.log(end3.toString()); // 13:58:41

Time wrapping

If the time goes past midnight, it wraps around to the next day:

js

const start = Temporal.PlainTime.from("12:34:56");
const end = start.add({ hours: 12 });
console.log(end.toString()); // 00:34:56

Specifications

Specification
Temporal
# sec-temporal.plaintime.prototype.add

Browser compatibility

See also

Help improve MDN

Learn how to contribute

This page was last modified on by MDN contributors.