Temporal.PlainDateTime.compare()

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 Temporal.PlainDateTime.compare() static method returns a number (-1, 0, or 1) indicating whether the first date-time comes before, is the same as, or comes after the second date-time. Equivalent to first comparing their dates, then comparing their times if the dates are the same.

Syntax

js
Temporal.PlainDateTime.compare(dateTime1, dateTime2)

Parameters

dateTime1

A string, an object, or a Temporal.PlainDateTime instance representing the first date-time to compare. It is converted to a Temporal.PlainDateTime object using the same algorithm as Temporal.PlainDateTime.from().

dateTime2

The second date-time to compare, converted to a Temporal.PlainDateTime object using the same algorithm as dateTime1.

Return value

Returns -1 if dateTime1 comes before dateTime2, 0 if they are the same, and 1 if dateTime2 comes after. They are compared by their underlying date and time values, ignoring their calendars.

Examples

Using Temporal.PlainDateTime.compare()

js
const dt1 = Temporal.PlainDateTime.from("2021-08-01T01:00:00");
const dt2 = Temporal.PlainDateTime.from("2021-08-02T00:00:00");
console.log(Temporal.PlainDateTime.compare(dt1, dt2)); // -1

const dt3 = Temporal.PlainDateTime.from("2021-08-01T00:00:00");
console.log(Temporal.PlainDateTime.compare(dt1, dt3)); // 1

Comparing dates in different calendars

js
const dt1 = Temporal.PlainDateTime.from({ year: 2021, month: 8, day: 1 });
const dt2 = Temporal.PlainDateTime.from({
  year: 2021,
  month: 8,
  day: 1,
  calendar: "islamic",
});
const dt3 = Temporal.PlainDateTime.from({
  year: 2021,
  month: 8,
  day: 1,
  calendar: "hebrew",
});
console.log(dt1.toString()); // "2021-08-01T00:00:00"
console.log(dt2.toString()); // "2582-12-17T00:00:00[u-ca=islamic]"
console.log(dt3.toString()); // "-001739-04-06T00:00:00[u-ca=hebrew]"
console.log(Temporal.PlainDateTime.compare(dt1, dt2)); // -1
console.log(Temporal.PlainDateTime.compare(dt1, dt3)); // 1

Sorting an array of date-times

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

js
const dateTimes = [
  Temporal.PlainDateTime.from("2021-08-01"),
  Temporal.PlainDateTime.from("2021-08-02"),
  Temporal.PlainDateTime.from("2021-08-01T01:00:00"),
];

dateTimes.sort(Temporal.PlainDateTime.compare);
console.log(dateTimes.map((d) => d.toString()));
// [ "2021-08-01T00:00:00", "2021-08-01T01:00:00", "2021-08-02T00:00:00" ]

Specifications

Specification
Temporal proposal
# sec-temporal.plaindatetime.compare

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobileserver
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
Deno
Node.js
compare
Experimental

Legend

Tip: you can click/tap on a cell for more information.

No support
No support
Experimental. Expect behavior to change in the future.
See implementation notes.
User must explicitly enable this feature.

See also