Temporal.PlainYearMonth.prototype.toPlainDate()

Limited availability

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

See full compatibility

The toPlainDate() method of Temporal.PlainYearMonth instances returns a new Temporal.PlainDate object representing this year-month and a supplied day in the same calendar system.

Syntax

toPlainDate(dayInfo)

Parameters

dayInfo Optional

An object representing the day component of the resulting PlainDate, containing the following property:

day: Corresponds to the day property.

Return value

A new Temporal.PlainDate object representing the date specified by this year-month and the day in dayInfo, interpreted in the calendar system of this year-month.

Exceptions

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

Examples

Using toPlainDate()

const ym = Temporal.PlainYearMonth.from("2021-07");
const date = ym.toPlainDate({ day: 1 });
console.log(date.toString()); // 2021-07-01

const ym2 = Temporal.PlainYearMonth.from("2021-07-01[u-ca=chinese]");
const date2 = ym2.toPlainDate({ day: 15 });
console.log(date2.toString()); // 2021-06-24[u-ca=chinese]

Specifications

Specification
Temporal # sec-temporal.plainyearmonth.prototype.toplaindate

Browser compatibility

	desktop					mobile							server
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on iOS	Samsung Internet	WebView Android	WebView on iOS	Bun	Deno	Node.js
`toPlainDate`	Chrome – Full support Chrome 144 (Release date: 2026-01-13) footnote Full support	Edge – Full support Edge 144 (Release date: 2026-01-21) footnote Full support	Firefox – Full support Firefox 139 (Release date: 2025-05-27) footnote Full support	Opera – Full support Opera 128 (Release date: 2026-02-26) footnote Full support	Safari – No support Safari footnote footnote See bug 223166	Chrome Android – Full support Chrome Android 144 (Release date: 2026-01-13) footnote Full support	Firefox for Android – Full support Firefox for Android 139 (Release date: 2025-05-27) footnote Full support	Opera Android – Full support Opera Android 95 (Release date: 2026-02-11) footnote Full support	Safari on iOS – No support Safari on iOS footnote footnote See bug 223166	Samsung Internet – No support Samsung Internet footnote No support	WebView Android – Full support WebView Android 144 (Release date: 2026-01-13) footnote Full support	WebView on iOS – No support WebView on iOS footnote footnote See bug 223166	Bun – No support Bun footnote No support	Deno – Full support Deno 2.7 (Release date: 2026-02-25) footnote Full support	Node.js – No support Node.js footnote No support

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Full support: Full support
No support: No support
: See implementation notes.

Temporal.PlainYearMonth.prototype.toPlainDate()

Legend