Temporal Conversion Rules
The table below shows how Temporal types can be converted.
| Col 1 | Col 2 | Col 3 | Col 4 | Col 5 | Col 6 |
|---|---|---|---|---|---|
| From | Plain Date | Plain Time | Plain DateTime | Zoned DateTime | Instant |
| PlainDate | No | Yes | No | No | |
| PlainTime | No | No | No | No | |
| PlainDateTime | Yes | Yes | Yes | No | |
| ZonedDateTime | Yes | Yes | Yes | Yes | |
| Instant | No | No | No | Yes |
Conversion Methods
| Col 1 | Col 2 | Col 3 |
|---|---|---|
| From | To | Method |
| Date | Instant | date.toTemporalInstant() |
| PlainDate | PlainTime | None |
| PlainDate | PlainDateTime | date.toPlainDateTime() |
| PlainDate | ZonedTime | None |
| PlainDate | Instant | None |
| PlainYearMonth | PlainDate | yearmonth.toPlainDate() |
| PlainMonthDay | PlainDate | monthday.toPlainDate() |
| PlainDateTime | PlainDate | datetime.toPlainDate() |
| PlainDateTime | PlainTime | datetime.toPlainTime() |
| PlainDateTime | ZonedDateTime | datetime.toZonedDateTime() |
| PlainDateTime | Instant | None |
| ZonedDateTime | PlainDate | zoned.toPlainDate() |
| ZonedDateTime | PlainDateTime | zoned.toPlainDateTime() |
| ZonedDateTime | PlainTime | zoned.toPlainTime() |
| ZonedDateTime | Instant | zoned.toInstant() |
| Instant | ZonedDateTime | zoned.toZonedDateTimeISO() |
Legacy Date to Temporal Instant
Example
const legacyDate = new Date();
const instant = legacyDate.toTemporalInstant();
PlainDate to PlainDateTime
You might like to add a time.
Examples
const date = Temporal.PlainDate.from("2026-05-17");
const dateTime = date.toPlainDateTime();
Combine Date and Time
You can combine PlainDate and PlainTime to create a PlainDateTime object.
Example
// Create a PlainDate object
const date = Temporal.PlainDate.from("2026-05-17");
// Create a PlainTime object
const time = Temporal.PlainTime.from("14:30");
// Convert into a PlainDateTime object
const dateTime = date.toPlainDateTime(time);
PlainDateTime to PlainDate
Example
const dateTime = Temporal.PlainDateTime.from("2026-05-17T14:30");
const date = dateTime.toPlainDate();
PlainDateTime to PlainTime
Example
const dateTime = Temporal.PlainDateTime.from("2026-05-17T14:30");
const time = dateTime.toPlainTime();
PlainDateTime to ZonedDateTime
PlainDateTime does not contain a time zone.
You must provide one to create a ZonedDateTime.
Wrong
const dateTime = Temporal.PlainDateTime.from("2026-05-17T14:30");
const zoned = dateTime.toZonedDateTime();
ZonedDateTime to PlainDateTime
Example
const zoned = Temporal.ZonedDateTime.from("2026-05-17T14:30:00+02:00[Europe/Oslo]");
const dateTime = zoned.toPlainDateTime();
ZonedDateTime to PlainDate
Example
const zoned = Temporal.ZonedDateTime.from("2026-05-17T14:30:00+02:00[Europe/Oslo]");
const date = zoned.toPlainDate();
ZonedDateTime to PlainTime
Example
const zoned = Temporal.ZonedDateTime.from("2026-05-17T14:30:00+02:00[Europe/Oslo]");
const time = zoned.toPlainTime();
ZonedDateTime to Instant
Example
const zoned = Temporal.ZonedDateTime.from("2026-05-17T14:30:00+02:00[Europe/Oslo]");
const instant = zoned.toInstant();
Instant to ZonedDateTime
Instant does not have a toZonedDateTime() method.
You must convert it to a ISO zone first.
Wrong
const instant = Temporal.Instant.from("2026-05-17T12:30:00Z");
const zoned = instant.toZonedDateTime("Europe/Oslo");
Special Temporal Types
| Col 1 | Col 2 | Col 3 | Col 4 |
|---|---|---|---|
| From | toPlainDate() | toPlainDateTime() | toZonedDateTime() |
| PlainYearMonth | YES + day value | No | No |
| PlainMonthDay | YES + year value | No | No |
Note: PlainMonthDay and PlainYearMonth need missing parts before becoming a full date.
PlainYearMonth to PlainDate
Example
const yearMonth = new Temporal.PlainYearMonth(2026, 5);
const date = yearMonth.toPlainDate({ day: 17 });
PlainMonthDay to PlainDate
Example
const monthDay = new Temporal.PlainYearMonth(2026, 5);
const date = monthDay.toPlainDate({ year: 2026 });
Time Zone Conversion
Converting time from another time zone is handled by the ZonedDateTime method withTimeZone().
Example
const zdtOslo = Temporal.Now.zonedDateTimeISO('Europe/Oslo');
const zdtTokyo = zdtOslo.withTimeZone('Asia/Tokyo');
