This feature is not Baseline because it does not work in some of the most widely-used browsers.
The inLeapYear accessor property of Temporal.ZonedDateTime instances returns a boolean indicating whether this date is in a leap year. A leap year is a year that has more days (due to a leap day or leap month) than a common year. It is calendar-dependent.
The set accessor of inLeapYear is undefined. You cannot change this property directly.
For general information and more examples, see Temporal.PlainDate.prototype.inLeapYear.
const dt = Temporal.ZonedDateTime.from("2021-07-01[America/New_York]");
console.log(dt.inLeapYear); // false
console.log(dt.daysInYear); // 365
console.log(dt.monthsInYear); // 12
| 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 | |
inLeapYear |
144 | 144 | 139 | No | No | 144 | 139 | No | No | No | 144 | No | ? | 1.40 | No |
Temporal.ZonedDateTimeTemporal.ZonedDateTime.prototype.with()Temporal.ZonedDateTime.prototype.add()Temporal.ZonedDateTime.prototype.subtract()Temporal.ZonedDateTime.prototype.yearTemporal.ZonedDateTime.prototype.daysInYearTemporal.ZonedDateTime.prototype.monthsInYearTemporal.PlainDate.prototype.inLeapYear
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https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Temporal/ZonedDateTime/inLeapYear