Temporal.ZonedDateTime.prototype.eraYear

The eraYear accessor property of {{jsxref("Temporal.ZonedDateTime")}} instances returns a non-negative integer representing the year of this date within the era, or undefined if the calendar does not use eras (e.g., ISO 8601). The year index usually starts from 1 (more common) or 0, and years in an era can decrease with time (e.g., Gregorian BCE). era and eraYear together uniquely identify a year in a calendar, in the same way that year does. It is calendar-dependent.

The set accessor of eraYear is undefined. You cannot change this property directly. Use the {{jsxref("Temporal/ZonedDateTime/with", "with()")}} method to create a new Temporal.ZonedDateTime object with the desired new value.

For general information and more examples, see {{jsxref("Temporal/PlainDate/eraYear", "Temporal.PlainDate.prototype.eraYear")}}.

Examples#

Using eraYear#

const dt = Temporal.ZonedDateTime.from("2021-07-01[America/New_York]"); // ISO 8601 calendar
console.log(dt.eraYear); // undefined

const dt2 = Temporal.ZonedDateTime.from(
  "2021-07-01[America/New_York][u-ca=gregory]",
);
console.log(dt2.eraYear); // 2021

const dt3 = Temporal.ZonedDateTime.from(
  "-002021-07-01[America/New_York][u-ca=gregory]",
);
console.log(dt3.eraYear); // 2022; 0000 is used for the year 1 BC

const dt4 = Temporal.ZonedDateTime.from(
  "2021-07-01[America/New_York][u-ca=japanese]",
);
console.log(dt4.eraYear); // 3

Specifications#

{{Specifications}}

Browser compatibility#

{{Compat}}

See also#

• {{jsxref("Temporal.ZonedDateTime")}}
• {{jsxref("Temporal/ZonedDateTime/with", "Temporal.ZonedDateTime.prototype.with()")}}
• {{jsxref("Temporal/ZonedDateTime/add", "Temporal.ZonedDateTime.prototype.add()")}}
• {{jsxref("Temporal/ZonedDateTime/subtract", "Temporal.ZonedDateTime.prototype.subtract()")}}
• {{jsxref("Temporal/ZonedDateTime/year", "Temporal.ZonedDateTime.prototype.year")}}
• {{jsxref("Temporal/ZonedDateTime/era", "Temporal.ZonedDateTime.prototype.era")}}
• {{jsxref("Temporal/PlainDate/eraYear", "Temporal.PlainDate.prototype.eraYear")}}