Temporal.PlainDateTime.prototype.eraYear

The eraYear accessor property of Temporal.PlainDateTime 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 with() method to create a new Temporal.PlainDateTime object with the desired new value.

For general information and more examples, see Temporal.PlainDate.prototype.eraYear.

Examples

Using eraYear

const dt = Temporal.PlainDateTime.from("2021-07-01"); // ISO 8601 calendar
console.log(dt.eraYear); // undefined

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

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

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

Specifications

Browser compatibility

See also

• Temporal.PlainDateTime
• Temporal.PlainDateTime.prototype.with()
• Temporal.PlainDateTime.prototype.add()
• Temporal.PlainDateTime.prototype.subtract()
• Temporal.PlainDateTime.prototype.year
• Temporal.PlainDateTime.prototype.era
• Temporal.PlainDate.prototype.eraYear