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Temporal.PlainDate.compare()

Limited availability

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

The Temporal.PlainDate.compare() static method returns a number (-1, 0, or 1) indicating whether the first date comes before, is the same as, or comes after the second date. Equivalent to comparing the year, month, and day fields of the underlying ISO 8601 dates.

Syntax

Temporal.PlainDate.compare(date1, date2)

Parameters

date1: A string, an object, or a Temporal.PlainDate instance representing the first date to compare. It is converted to a Temporal.PlainDate object using the same algorithm as Temporal.PlainDate.from().
date2: The second date to compare, converted to a Temporal.PlainDate object using the same algorithm as date1.

Return value

Returns -1 if date1 comes before date2, 0 if they are the same, and 1 if date1 comes after date2. They are compared by their underlying date values, ignoring their calendars.

Examples

Using Temporal.PlainDate.compare()

const date1 = Temporal.PlainDate.from("2021-08-01");
const date2 = Temporal.PlainDate.from("2021-08-02");
console.log(Temporal.PlainDate.compare(date1, date2)); // -1

const date3 = Temporal.PlainDate.from("2021-07-31");
console.log(Temporal.PlainDate.compare(date1, date3)); // 1

Comparing dates in different calendars

const date1 = Temporal.PlainDate.from({ year: 2021, month: 8, day: 1 });
const date2 = Temporal.PlainDate.from({
  year: 2021,
  month: 8,
  day: 1,
  calendar: "islamic-umalqura",
});
const date3 = Temporal.PlainDate.from({
  year: 2021,
  month: 8,
  day: 1,
  calendar: "hebrew",
});
console.log(date1.toString()); // "2021-08-01"
console.log(date2.toString()); // "2582-12-17[u-ca=islamic-umalqura]"
console.log(date3.toString()); // "-001739-04-06[u-ca=hebrew]"
console.log(Temporal.PlainDate.compare(date1, date2)); // -1
console.log(Temporal.PlainDate.compare(date1, date3)); // 1

Sorting an array of dates

The purpose of this compare() function is to act as a comparator to be passed to Array.prototype.sort() and related functions.

const dates = [
  Temporal.PlainDate.from({ year: 2021, month: 8, day: 1 }),
  Temporal.PlainDate.from({
    year: 2021,
    month: 8,
    day: 1,
    calendar: "islamic-umalqura",
  }),
  Temporal.PlainDate.from({ year: 2021, month: 8, day: 1, calendar: "hebrew" }),
];

dates.sort(Temporal.PlainDate.compare);
console.log(dates.map((d) => d.toString()));
// [ "-001739-04-06[u-ca=hebrew]", "2021-08-01", "2582-12-17[u-ca=islamic-umalqura]" ]

Specifications

Specification
Temporal> # sec-temporal.plaindate.compare>

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
`compare`	144	144	139	No	No	144	139	No	No	No	144	No	?	1.40	No