A Temporal.PlainDate represents a calendar date.
"Calendar date" refers to the concept of a date as expressed in everyday usage, independent of any time zone.
For example, it could be used to represent an event on a calendar which happens during the whole day no matter which time zone it's happening in.
Temporal.PlainDate refers to the whole of a specific day; if you need to refer to a specific time on that day, use Temporal.PlainDateTime.
A Temporal.PlainDate can be converted into a Temporal.ZonedDateTime by combining it with a Temporal.PlainTime and time zone identifier using the toZonedDateTime() method.
It can also be combined with a Temporal.PlainTime to yield a "zoneless" Temporal.PlainDateTime using the toPlainDateTime() method.
Temporal.PlainYearMonth and Temporal.PlainMonthDay carry less information than Temporal.PlainDate and should be used when complete information is not required.
Parameters:
isoYear (number): A year.isoMonth (number): A month, ranging between 1 and 12 inclusive.isoDay (number): A day of the month, ranging between 1 and 31 inclusive.calendar (optional string): A calendar to project the date into.Returns: a new Temporal.PlainDate object.
Use this constructor if you have the correct parameters for the date already as individual number values in the ISO 8601 calendar.
Otherwise, Temporal.PlainDate.from(), which accepts more kinds of input, allows inputting dates in different calendar reckonings, and allows controlling the overflow behavior, is probably more convenient.
All values are given as reckoned in the ISO 8601 calendar.
Together, isoYear, isoMonth, and isoDay must represent a valid date in that calendar, even if you are passing a different calendar as the calendar parameter.
The range of allowed values for this type is exactly enough that calling toPlainDate() on any valid Temporal.PlainDateTime will succeed.
If isoYear, isoMonth, and isoDay form a date outside of this range, then this function will throw a RangeError.
calendar is a string containing the identifier of a built-in calendar, such as 'islamic' or 'gregory'.
NOTE: The
isoMonthargument ranges from 1 to 12, which is different from legacyDatewhere months are represented by zero-based indices (0 to 11).
Usage examples:
// Pi day in 2020
date = new Temporal.PlainDate(2020, 3, 14); // => 2020-03-14Parameters:
item: a value convertible to a Temporal.PlainDate.options (optional object): An object with properties representing options for constructing the date.
The following options are recognized:overflow (string): How to deal with out-of-range values if item is an object.
Allowed values are 'constrain' and 'reject'.
The default is 'constrain'.Returns: a new Temporal.PlainDate object.
This static method creates a new Temporal.PlainDate object from another value.
If the value is another Temporal.PlainDate object, a new object representing the same date is returned.
If the value is any other object, it:
year property or (for calendars that support eras) an era and eraYear property.month property or a string monthCode property.calendar property. If omitted, the ISO 8601 calendar will be used by default.If the value is not an object, it must be a string, which is expected to be in ISO 8601 format.
Any time part is optional and will be ignored.
Time zone or UTC offset information will also be ignored, with one exception: if a string contains a Z in place of a numeric UTC offset, then a RangeError will be thrown because interpreting these strings as a local date and time is usually a bug. Temporal.Instant.from should be used instead to parse these strings, and the result's toZonedDateTimeISO method can be used to obtain a timezone-local date and time.
In unusual cases of needing date or time components of Z-terminated timestamp strings (e.g. daily rollover of a UTC-timestamped log file), use the time zone 'UTC'. For example, the following code returns a "UTC date": Temporal.Instant.from(item).toZonedDateTimeISO('UTC').toPlainDate().
If the string isn't valid according to ISO 8601, then a RangeError will be thrown regardless of the value of overflow.
The overflow option works as follows, if item is an object:
'constrain' mode (the default), any out-of-range values are clamped to the nearest in-range value (after assuming extension of eras over arbitrary years to substitute era and eraYear with appropriate values for the item).'reject' mode, the presence of out-of-range values (after assuming extension of eras over arbitrary years to substitute era and eraYear with appropriate values for the item) will cause the function to throw a RangeError.The overflow option is ignored if item is a string.
Additionally, if the result is earlier or later than the range of dates that Temporal.PlainDate can represent (approximately half a million years centered on the Unix epoch), then this function will throw a RangeError regardless of overflow.
NOTE: The allowed values for the
item.monthproperty start at 1, which is different from legacyDatewhere months are represented by zero-based indices (0 to 11).
Example usage:
date = Temporal.PlainDate.from('2006-08-24'); // => 2006-08-24
date = Temporal.PlainDate.from('20060824'); // => 2006-08-24
date = Temporal.PlainDate.from('2006-08-24T15:43:27'); // => 2006-08-24
date = Temporal.PlainDate.from('2006-08-24T15:43:27+01:00[Europe/Brussels]');
// => 2006-08-24
date === Temporal.PlainDate.from(date); // => false
date = Temporal.PlainDate.from({ year: 2006, month: 8, day: 24 }); // => 2006-08-24
date = Temporal.PlainDate.from(Temporal.PlainDateTime.from('2006-08-24T15:43:27'));
// => 2006-08-24
// same as above; Temporal.PlainDateTime has year, month, and day properties
date = Temporal.PlainDate.from({ year: 1427, month: 8, day: 1, calendar: 'islamic' });
// => 2006-08-24[u-ca=islamic]
// Different overflow modes
date = Temporal.PlainDate.from({ year: 2001, month: 13, day: 1 }, { overflow: 'constrain' });
// => 2001-12-01
date = Temporal.PlainDate.from({ year: 2001, month: 1, day: 32 }, { overflow: 'constrain' });
// => 2001-01-31
date = Temporal.PlainDate.from({ year: 2001, month: 13, day: 1 }, { overflow: 'reject' });
// => throws
date = Temporal.PlainDate.from({ year: 2001, month: 1, day: 32 }, { overflow: 'reject' });
// => throwsParameters:
one (Temporal.PlainDate or value convertible to one): First date to compare.two (Temporal.PlainDate or value convertible to one): Second date to compare.Returns: −1, 0, or 1.
Compares two Temporal.PlainDate objects.
Returns an integer indicating whether one comes before or after or is equal to two.
one comes before twoone and two are the same date when projected into the ISO 8601 calendarone comes after twoIf one or two are not Temporal.PlainDate objects, then they will be converted to one as if they were passed to Temporal.PlainDate.from().
Calendars are ignored in the comparison.
For example, this method returns 0 for instances that fall on the same day in the ISO 8601 calendar, even if their calendars describe it with a different month, year, and/or day.
This function can be used to sort arrays of Temporal.PlainDate objects.
For example:
one = Temporal.PlainDate.from('2006-08-24');
two = Temporal.PlainDate.from('2015-07-14');
three = Temporal.PlainDate.from('1930-02-18');
sorted = [one, two, three].sort(Temporal.PlainDate.compare);
sorted.join(' '); // => '1930-02-18 2006-08-24 2015-07-14'The above read-only properties allow accessing each component of a date individually.
year is a signed integer representing the number of years relative to a calendar-specific epoch.
For calendars that use eras, the anchor is usually aligned with the latest era so that eraYear === year for all dates in that era.
However, some calendars use a different anchor (e.g., the Japanese calendar year matches the ISO 8601 and Gregorian calendars in counting from ISO year 0001 as 1).month is a positive integer representing the ordinal index of the month in the current year.
For calendars like Hebrew or Chinese that use leap months, the same-named month may have a different month value depending on the year.
The first month in every year has month equal to 1.
The last month of every year has month equal to the monthsInYear property.
month values start at 1, which is different from legacy Date where months are represented by zero-based indices (0 to 11).monthCode is a calendar-specific string that identifies the month in a year-independent way.
For common (non-leap) months, monthCode should be `M${month}`, where month is zero padded up to two digits.
For uncommon (leap) months in lunisolar calendars like Hebrew or Chinese, the month code is the previous month's code with an "L" suffix appended.
Examples: 'M02' => February; 'M08L' => repeated 8th month in the Chinese calendar; 'M05L' => Adar I in the Hebrew calendar.day is a positive integer representing the day of the month.Either month or monthCode can be used in from or with to refer to the month.
Similarly, in calendars that use eras, an era/eraYear pair can be used in place of year when calling from or with.
Usage examples:
date = Temporal.PlainDate.from('2006-08-24');
date.year; // => 2006
date.month; // => 8
date.monthCode; // => 'M08'
date.day; // => 24
date = Temporal.PlainDate.from('2019-02-23[u-ca=hebrew]');
date.year; // => 5779
date.month; // => 6
date.monthCode; // => 'M05L'
date.day; // => 18The calendarId read-only property gives the identifier of the calendar that the year, month, monthCode, and day properties are interpreted in.
In calendars that use eras, the era and eraYear read-only properties can be used together to resolve an era-relative year.
Both properties are undefined when using the ISO 8601 calendar.
As inputs to from or with, era and eraYear can be used instead of year.
Unlike year, eraYear may decrease as time proceeds because some eras (like the BCE era in the Gregorian calendar) count years backwards.
date = Temporal.PlainDate.from('-000015-01-01[u-ca=gregory]');
date.era;
// => 'bce'
date.eraYear;
// => 16
date.year;
// => -15The dayOfWeek read-only property gives the weekday number that the date falls on.
For the ISO 8601 calendar, the weekday number is defined as in the ISO 8601 standard: a value between 1 and 7, inclusive, with Monday being 1, and Sunday 7.
For an overview, see ISO 8601 on Wikipedia.
Usage example:
date = Temporal.PlainDate.from('2006-08-24');
['MON', 'TUE', 'WED', 'THU', 'FRI', 'SAT', 'SUN'][date.dayOfWeek - 1]; // => 'THU'The dayOfYear read-only property gives the ordinal day of the year that the date falls on.
For the ISO 8601 calendar, this is a value between 1 and 365, or 366 in a leap year.
Usage example:
date = Temporal.PlainDate.from('2006-08-24');
// ISO ordinal date
console.log(date.year, date.dayOfYear); // => '2006 236'The weekOfYear read-only property gives the ISO week number of the date.
For the ISO 8601 calendar, this is normally a value between 1 and 52, but in a few cases it can be 53 as well.
ISO week 1 is the week containing the first Thursday of the year.
For more information on ISO week numbers, see for example the Wikipedia article on ISO week date.
When combining the week number with a year number, make sure to use date.yearOfWeek instead of date.year.
This is because the first few days of a calendar year may be part of the last week of the previous year, and the last few days of a calendar year may be part of the first week of the new year, depending on which year the first Thursday falls in.
Usage example:
date = Temporal.PlainDate.from('2022-01-01');
// ISO week date
console.log(date.yearOfWeek, date.weekOfYear, date.dayOfWeek); // => '2021 52 6'The yearOfWeek read-only property gives the ISO "week calendar year" of the date, which is the year number corresponding to the ISO week number.
For the ISO 8601 calendar, this is normally the same as date.year, but in a few cases it may be the previous or following year.
For more information on ISO week numbers, see for example the Wikipedia article on ISO week date.
See weekOfYear for a usage example.
The daysInWeek read-only property gives the number of days in the week that the date falls in.
For the ISO 8601 calendar, this is always 7, but in other calendar systems it may differ from week to week.
Usage example:
date = Temporal.PlainDate.from('2006-08-24');
date.daysInWeek; // => 7The daysInMonth read-only property gives the number of days in the month that the date falls in.
For the ISO 8601 calendar, this is 28, 29, 30, or 31, depending on the month and whether the year is a leap year.
Usage example:
// Attempt to write some mnemonic poetry
const monthsByDays = {};
for (let month = 1; month <= 12; month++) {
const date = Temporal.Now.plainDateISO().with({ month });
monthsByDays[date.daysInMonth] = (monthsByDays[date.daysInMonth] || []).concat(date);
}
const strings = monthsByDays[30].map((date) => date.toLocaleString('en', { month: 'long' }));
// Shuffle to improve poem as determined empirically
strings.unshift(strings.pop());
const format = new Intl.ListFormat('en');
const poem = `Thirty days hath ${format.format(strings)}`;
console.log(poem);The daysInYear read-only property gives the number of days in the year that the date falls in.
For the ISO 8601 calendar, this is 365 or 366, depending on whether the year is a leap year.
Usage example:
date = Temporal.Now.plainDateISO();
percent = date.dayOfYear / date.daysInYear;
`The year is ${percent.toLocaleString('en', { style: 'percent' })} over!`;
// example output: "The year is 10% over!"The monthsInYear read-only property gives the number of months in the year that the date falls in.
For the ISO 8601 calendar, this is always 12, but in other calendar systems it may differ from year to year.
Usage example:
date = Temporal.PlainDate.from('1900-01-01');
date.monthsInYear; // => 12The inLeapYear read-only property tells whether the year that the date falls in is a leap year or not.
Its value is true if the year is a leap year, and false if not.
NOTE: A "leap year" is a year that contains more days than other years (for solar or lunar calendars) or more months than other years (for lunisolar calendars like Hebrew or Chinese). In the ISO 8601 calendar, a year is a leap year (and has exactly one extra day, February 29) if it is evenly divisible by 4 but not 100 or if it is evenly divisible by 400.
Usage example:
// Is this year a leap year?
date = Temporal.Now.plainDateISO();
date.inLeapYear; // example output: true
// Is 2100 a leap year? (no, because it's divisible by 100 and not 400)
date.with({ year: 2100 }).inLeapYear; // => falseParameters:
dateLike (object): an object with some or all of the properties of a Temporal.PlainDate.options (optional object): An object with properties representing options for the operation.
The following options are recognized:overflow (string): How to deal with out-of-range values.
Allowed values are 'constrain' and 'reject'.
The default is 'constrain'.Returns: a new Temporal.PlainDate object.
This method creates a new Temporal.PlainDate which is a copy of date, but any properties present on dateLike override the ones already present on date.
Since Temporal.PlainDate objects each represent a fixed date, use this method instead of modifying one.
If the result is earlier or later than the range of dates that Temporal.PlainDate can represent (approximately half a million years centered on the Unix epoch), then this method will throw a RangeError regardless of overflow.
NOTE: The allowed values for the
dateLike.monthproperty start at 1, which is different from legacyDatewhere months are represented by zero-based indices (0 to 11).
NOTE:
calendarandtimeZoneproperties are not allowed ondateLike. See thewithCalendarandtoZonedDateTimemethods instead.
Usage example:
date = Temporal.PlainDate.from('2006-01-24');
// What's the first day of this month?
date.with({ day: 1 }); // => 2006-01-01
// What's the last day of the next month?
const nextMonthDate = date.add({ months: 1 });
nextMonthDate.with({ day: nextMonthDate.daysInMonth }); // => 2006-02-28Parameters:
calendar (object or string): The calendar into which to project date.Returns: a new Temporal.PlainDate object which is the date indicated by date, projected into calendar.
Usage example:
date = Temporal.PlainDate.from('2006-08-24[u-ca=japanese]');
date.withCalendar('iso8601'); // => 2006-08-24Parameters:
duration (Temporal.Duration or value convertible to one): The duration to add.options (optional object): An object with properties representing options for the addition.
The following options are recognized:overflow (optional string): How to deal with additions that result in out-of-range values.
Allowed values are 'constrain' and 'reject'.
The default is 'constrain'.Returns: a new Temporal.PlainDate object which is the date indicated by date plus duration.
This method adds duration to date, returning a date that is in the future relative to date.
The duration argument is an object with properties denoting a duration, such as { days: 5 }, or a string such as P5D, or a Temporal.Duration object.
If duration is not a Temporal.Duration object, then it will be converted to one as if it were passed to Temporal.Duration.from().
If duration has any units smaller than days, they will be treated as if they are being added to the first moment of the day given by date.
Effectively, this means that adding things like { minutes: 5 } will be ignored.
Some additions may be ambiguous, because months have different lengths.
For example, adding one month to August 31 would result in September 31, which doesn't exist.
For these cases, the overflow option tells what to do:
'constrain' mode (the default), out-of-range values are clamped to the nearest in-range value.'reject' mode, an addition that would result in an out-of-range value fails, and a RangeError is thrown.Additionally, if the result is earlier or later than the range of dates that Temporal.PlainDate can represent (approximately half a million years centered on the Unix epoch), then this method will throw a RangeError regardless of overflow.
Adding a negative duration is equivalent to subtracting the absolute value of that duration.
Usage example:
date = Temporal.PlainDate.from('2006-08-24');
date.add({ years: 20, months: 4 }); // => 2026-12-24
date = Temporal.PlainDate.from('2019-01-31');
date.add({ months: 1 }); // => 2019-02-28
date.add({ months: 1 }, { overflow: 'reject' }); // => throwsParameters:
duration (Temporal.Duration or value convertible to one): The duration to subtract.options (optional object): An object with properties representing options for the subtraction.
The following options are recognized:overflow (string): How to deal with subtractions that result in out-of-range values.
Allowed values are 'constrain' and 'reject'.
The default is 'constrain'.Returns: a new Temporal.PlainDate object which is the date indicated by date minus duration.
This method subtracts duration from date, returning a date that is in the past relative to date.
The duration argument is an object with properties denoting a duration, such as { days: 5 }, or a string such as P5D, or a Temporal.Duration object.
If duration is not a Temporal.Duration object, then it will be converted to one as if it were passed to Temporal.Duration.from().
If duration has any units smaller than days, they will be treated as if they are being subtracted from the last moment of the day given by date.
Effectively, this means that subtracting things like { minutes: 5 } will be ignored.
Some subtractions may be ambiguous, because months have different lengths.
For example, subtracting one month from July 31 would result in June 31, which doesn't exist.
For these cases, the overflow option tells what to do:
'constrain' mode (the default), out-of-range values are clamped to the nearest in-range value.'reject' mode, an addition that would result in an out-of-range value fails, and a RangeError is thrown.Additionally, if the result is earlier or later than the range of dates that Temporal.PlainDate can represent (approximately half a million years centered on the Unix epoch), then this method will throw a RangeError regardless of overflow.
Subtracting a negative duration is equivalent to adding the absolute value of that duration.
Usage example:
date = Temporal.PlainDate.from('2006-08-24');
date.subtract({ years: 20, months: 4 }); // => 1986-04-24
date = Temporal.PlainDate.from('2019-03-31');
date.subtract({ months: 1 }); // => 2019-02-28
date.subtract({ months: 1 }, { overflow: 'reject' }); // => throwsParameters:
other (Temporal.PlainDate or value convertible to one): Another date until when to compute the difference.options (optional object): An object with properties representing options for the operation.
The following options are recognized:largestUnit (optional string): The largest unit of time to allow in the resulting Temporal.Duration object.
Valid values are 'auto', 'year', 'month', 'week', and 'day'.
The default is 'auto'.smallestUnit (string): The smallest unit of time to round to in the resulting Temporal.Duration object.
Valid values are 'year', 'month', 'week', 'day'.
The default is 'day', i.e., no rounding.roundingIncrement (number): The granularity to round to, of the unit given by smallestUnit.
The default is 1.roundingMode (string): How to handle the remainder, if rounding.
Valid values are 'ceil', 'floor', 'expand', 'trunc', 'halfCeil', 'halfFloor', 'halfExpand', 'halfTrunc', and 'halfEven'.
The default is 'trunc', which truncates any remainder towards zero.Returns: a Temporal.Duration representing the time elapsed after date and until other.
This method computes the difference between the two dates represented by date and other, optionally rounds it, and returns it as a Temporal.Duration object.
If other is earlier than date then the resulting duration will be negative.
If using the default options, adding the returned Temporal.Duration to date will yield other.
If other is not a Temporal.PlainDate object, then it will be converted to one as if it were passed to Temporal.PlainDate.from().
The largestUnit option controls how the resulting duration is expressed.
The returned Temporal.Duration object will not have any nonzero fields that are larger than the unit in largestUnit.
A difference of two years will become 24 months when largestUnit is 'months', for example.
However, a difference of two months will still be two months even if largestUnit is 'years'.
A value of 'auto' means 'day', unless smallestUnit is 'year', 'month', or 'week', in which case largestUnit is equal to smallestUnit.
By default, the largest unit in the result is days. This is because months and years can be different lengths depending on which month is meant and whether the year is a leap year.
You can round the result using the smallestUnit, roundingIncrement, and roundingMode options.
These behave as in the Temporal.Duration.round() method, but increments of days and larger are allowed.
Because rounding to calendar units requires a reference point, date is used as the starting point.
The default is to do no rounding.
For rounding purposes, a Temporal.PlainDate instance will be treated the same as a Temporal.PlainDateTime instance with the time set to midnight.
Therefore when rounding using the 'halfExpand' rounding mode, dates at the exact midpoint of the smallestUnit will be rounded down.
Unlike other Temporal types, hours and lower are not allowed for either largestUnit or smallestUnit, because the data model of Temporal.PlainDate doesn't have that accuracy.
Computing the difference between two dates in different calendar systems is not supported.
If you need to do this, choose the calendar in which the computation takes place by converting one of the dates with date.withCalendar().
Usage example:
earlier = Temporal.PlainDate.from('2006-08-24');
later = Temporal.PlainDate.from('2019-01-31');
earlier.until(later); // => P4543D
earlier.until(later, { largestUnit: 'year' }); // => P12Y5M7D
later.until(earlier, { largestUnit: 'year' }); // => -P12Y5M7D
// If you really need to calculate the difference between two Dates in
// hours, you can eliminate the ambiguity by explicitly choosing the
// point in time from which you want to reckon the difference. For
// example, using noon:
noon = Temporal.PlainTime.from('12:00');
earlier.toPlainDateTime(noon).until(later.toPlainDateTime(noon), { largestUnit: 'hour' });
// => PT109032H
newyear = Temporal.PlainDate.from('2020-01-01');
newyear.until('2020-01-15', { smallestUnit: 'month', roundingMode: 'halfExpand' });
// => PT0S
newyear.until('2020-01-16', { smallestUnit: 'month', roundingMode: 'halfExpand' });
// => PT0S (mid-month dates rounded down to match `Temporal.PlainDateTime` behavior)
newyear.until('2020-01-17', { smallestUnit: 'month', roundingMode: 'halfExpand' });
// => PT1MParameters:
other (Temporal.PlainDate or value convertible to one): Another date since when to compute the difference.options (optional object): An object with properties representing options for the operation.
The following options are recognized:largestUnit (optional string): The largest unit of time to allow in the resulting Temporal.Duration object.
Valid values are 'auto', 'year', 'month', 'week', and 'day'.
The default is 'auto'.smallestUnit (string): The smallest unit of time to round to in the resulting Temporal.Duration object.
Valid values are 'year', 'month', 'week', 'day'.
The default is 'day', i.e., no rounding.roundingIncrement (number): The granularity to round to, of the unit given by smallestUnit.
The default is 1.roundingMode (string): How to handle the remainder, if rounding.
Valid values are 'ceil', 'floor', 'expand', 'trunc', 'halfCeil', 'halfFloor', 'halfExpand', 'halfTrunc', and 'halfEven'.
The default is 'trunc', which truncates any remainder towards zero.Returns: a Temporal.Duration representing the time elapsed before date and since other.
This method computes the difference between the two dates represented by date and other, optionally rounds it, and returns it as a Temporal.Duration object.
If other is later than date then the resulting duration will be negative.
This method is similar to Temporal.PlainDate.prototype.until(), but reversed.
If using the default options, subtracting the returned Temporal.Duration from date will yield other, and date1.since(date2) will yield the same result as date1.until(date2).negated().
Usage example:
earlier = Temporal.PlainDate.from('2006-08-24');
later = Temporal.PlainDate.from('2019-01-31');
later.since(earlier); // => P4543DParameters:
other (Temporal.PlainDate or value convertible to one): Another date to compare.Returns: true if date and other are equal, or false if not.
Compares two Temporal.PlainDate objects for equality.
This function exists because it's not possible to compare using date == other or date === other, due to ambiguity in the primitive representation and between Temporal types.
If you don't need to know the order in which the two dates occur, then this function may be less typing and more efficient than Temporal.PlainDate.compare.
Note that this function will return false if the two objects have different calendar properties, even if the actual dates are equal.
If other is not a Temporal.PlainDate object, then it will be converted to one as if it were passed to Temporal.PlainDate.from().
Example usage:
date = Temporal.PlainDate.from('2006-08-24');
other = Temporal.PlainDate.from('2019-01-31');
date.equals(other); // => false
date.equals(date); // => trueParameters:
options (optional object): An object with properties influencing the formatting.
The following options are recognized:calendarName (string): Whether to show the calendar annotation in the return value.
Valid values are 'auto', 'always', 'never', and 'critical'.
The default is 'auto'.Returns: a string in the ISO 8601 date format representing date.
This method overrides the Object.prototype.toString() method and provides a convenient, unambiguous string representation of date.
The string can be passed to Temporal.PlainDate.from() to create a new Temporal.PlainDate object.
Normally, a calendar annotation is shown when date's calendar is not the ISO 8601 calendar.
By setting the calendarName option to 'always' or 'never' this can be overridden to always or never show the annotation, respectively.
Normally not necessary, a value of 'critical' is equivalent to 'always' but the annotation will contain an additional ! for certain interoperation use cases.
For more information on the calendar annotation, see the Temporal string formats documentation.
Example usage:
date = Temporal.PlainDate.from('2006-08-24');
date.toString(); // => '2006-08-24'Parameters:
locales (optional string or array of strings): A string with a BCP 47 language tag with an optional Unicode extension key, or an array of such strings.options (optional object): An object with properties influencing the formatting.Returns: a language-sensitive representation of date.
This method overrides Object.prototype.toLocaleString() to provide a human-readable, language-sensitive representation of date.
The locales and options arguments are the same as in the constructor to Intl.DateTimeFormat.
Example usage:
date = Temporal.PlainDate.from('2006-08-24');
date.toLocaleString(); // example output: 8/24/2006
date.toLocaleString('de-DE'); // example output: '24.8.2006'
date.toLocaleString('de-DE', { weekday: 'long' }); // => 'Donnerstag'
date.toLocaleString('en-US-u-nu-fullwide'); // => '８/２４/２００６'Returns: a string in the ISO 8601 date format representing date.
This method is the same as date.toString().
It is usually not called directly, but it can be called automatically by JSON.stringify().
The reverse operation, recovering a Temporal.PlainDate object from a string, is Temporal.PlainDate.from(), but it cannot be called automatically by JSON.parse().
If you need to rebuild a Temporal.PlainDate object from a JSON string, then you need to know the names of the keys that should be interpreted as Temporal.PlainDates.
In that case you can build a custom "reviver" function for your use case.
Example usage:
const student = {
id: 429,
name: 'Emilia Connor',
birthDate: Temporal.PlainDate.from('1997-09-08')
};
const str = JSON.stringify(student, null, 2);
console.log(str);
// =>
// {
// "id": 429,
// "name": "Emilia Connor",
// "birthDate": "1997-09-08"
// }
// To rebuild from the string:
function reviver(key, value) {
if (key.endsWith('Date')) return Temporal.PlainDate.from(value);
return value;
}
JSON.parse(str, reviver);This method overrides Object.prototype.valueOf() and always throws an exception.
This is because it's not possible to compare Temporal.PlainDate objects with the relational operators <, <=, >, or >=.
Use Temporal.PlainDate.compare() for this, or date.equals() for equality.
Parameters:
item (object): an object with properties to be added to date. The following properties are recognized:plainTime (optional Temporal.PlainTime or value convertible to one): a time of day on date used to merge into a Temporal.ZonedDateTime.timeZone (required string or Temporal.ZonedDateTime): the time zone in which to interpret date and plainTime, as a time zone identifier, or a Temporal.ZonedDateTime object whose time zone will be used.Returns: a Temporal.ZonedDateTime object that represents the wall-clock time plainTime on the calendar date date projected into timeZone.
This method can be used to convert Temporal.PlainDate into a Temporal.ZonedDateTime, by supplying the time zone and time of day.
The default plainTime, if it's not provided, is the first valid local time in timeZone on the calendar date date.
Usually this is midnight (00:00), but may be a different time in rare circumstances like DST skipping midnight.
For a list of IANA time zone names, see the current version of the IANA time zone database. A convenient list is also available on Wikipedia, although it might not reflect the latest official status.
In addition to the timeZone, the converted object carries a copy of all the relevant fields of date and plainTime.
If plainTime is provided but is not a Temporal.PlainTime object, then it will be converted to one as if it were passed to Temporal.PlainTime.from().
If plainTime is provided, this method is equivalent to Temporal.PlainTime.from(plainTime).toPlainDateTime(date).toZonedDateTime(timeZone).
In the case of ambiguity caused by DST or other time zone changes, the earlier time will be used for backward transitions and the later time for forward transitions.
When interoperating with existing code or services, this matches the behavior of legacy Date as well as libraries like moment.js, Luxon, and date-fns.
This mode also matches the behavior of cross-platform standards like RFC 5545 (iCalendar).
During "skipped" clock time like the hour after DST starts in the Spring, this method interprets invalid times using the pre-transition time zone offset.
This behavior avoids exceptions when converting nonexistent date/time values to Temporal.ZonedDateTime, but it also means that values during these periods will result in a different Temporal.PlainTime value in "round-trip" conversions to Temporal.ZonedDateTime and back again.
For usage examples and a more complete explanation of how this disambiguation works, see Time Zones and Resolving Ambiguity.
If the result is outside the range that Temporal.ZonedDateTime can represent (approximately half a million years centered on the Unix epoch), then a RangeError will be thrown.
Usage example:
plainDate = Temporal.PlainDate.from('2006-08-24');
plainTime = Temporal.PlainTime.from('15:23:30.003');
plainDate.toZonedDateTime({ timeZone: 'America/Los_Angeles', plainTime });
// => 2006-08-24T15:23:30.003-07:00[America/Los_Angeles]
plainDate.toZonedDateTime({ timeZone: 'America/Los_Angeles' });
// => 2006-08-24T00:00:00-07:00[America/Los_Angeles]Parameters:
time (optional Temporal.PlainTime or value convertible to one): A time of day on date.Returns: a Temporal.PlainDateTime object that represents the wall-clock time time on the calendar date date.
This method can be used to convert Temporal.PlainDate into a Temporal.PlainDateTime, by supplying the time of day to use.
The default time, if it is not given, is midnight (00:00).
The converted object carries a copy of all the relevant fields of date and time.
If time is given, this is equivalent to Temporal.PlainTime.from(time).toPlainDateTime(date).
If time is given and is not a Temporal.PlainTime object, then it will be converted to one as if it were passed to Temporal.PlainTime.from().
Usage example:
date = Temporal.PlainDate.from('2006-08-24');
time = Temporal.PlainTime.from('15:23:30.003');
date.toPlainDateTime(time); // => 2006-08-24T15:23:30.003
date.toPlainDateTime(); // => 2006-08-24T00:00:00Returns: a Temporal.PlainYearMonth object that is the same as the year and month of date.
Returns: a Temporal.PlainMonthDay object that is the same as the month and day of date.
The above two methods can be used to convert Temporal.PlainDate into a Temporal.PlainYearMonth or Temporal.PlainMonthDay respectively.
The converted object carries a copy of all the relevant fields of date (for example, in toPlainYearMonth(), the year and month properties are copied.)
Usage example:
date = Temporal.PlainDate.from('2006-08-24');
date.toPlainYearMonth(); // => 2006-08
date.toPlainMonthDay(); // => 08-24