JavaScript PlainDateTime
The Temporal.PlainDateTime Object
The Temporal.PlainDateTime object is a pure date and time object.
It represents a calendar date and a wall-clock time with no time zone.
Example: 2026-05-07T14:30:00.
Example
// Create a PlainDateTime object
const dateTime = Temporal.PlainDateTime.from("2026-05-17T14:30:00");
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The T is a literal to separate the date from the time.
What You Will Learn:
- How to use JavaScript Temporal.PlainDateTime
- How to work with date and time without a time zone
- How to add and subtract dates
- How to compare dates safely
PlainDateTime is useful when you need both date and time, but not time zone.
How to Create a Temporal.PlainDateTime
An PlainDateTime object can be created in several different ways:
| From | Code |
|---|---|
| Constructor (new) | new Temporal.PlainDateTime() |
| ISO String | Temporal.PlainDate.from() |
| Now (current time) | Temporal.Now.plainDateTimeISO() |
Create a PlainDateTime with new
You can create a PlainDateTime object using new with parameters.
Example
// Create a PlainDateTime object
const date = new Temporal.PlainDateTime(2026, 5, 17, 14, 30);
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In Temporal objects, months start at 1.
In the legasy Date object, months start at 0.
Create a PlainDateTime from a String
You can create a PlainDateTime object from an ISO 8601 / RFC 9557 string.
Example
// Create a PlainDateTime object
const dateTime = Temporal.PlainDateTime.from("2026-05-17T10:00:00");
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The T Between Date and Time?
The T is a literal to separate the date from the time.
You should read it as an abbreviation for Time.
It is the separator required by the ISO 8601 format requires.
Create a PlainDateTime from Now
You can create a PlainDateTime object from current time.
Combine Date and Time
You can combine PlainDate and PlainTime to create a PlainDateTime.
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);
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Add or Subtract Time
You can safely add or subtract time.
The original value does not change.
Example
// Create a PlainDateTime object
const date = Temporal.PlainDateTime.from("2026-05-17T14:30:00");
// Add and subtract time
const earlier = dateTime.subtract({ minutes: 30 });
const later = dateTime.add({ hours: 2 });
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When to Use PlainDateTime
Applications where time zone conversion is not required.
Local event scheduling.
Appointments without international time zone handling.
Forms that collect date and time.
Compare PlainDateTime Values
You can compare PlaneDateTime values using the equals() method.
Example
const d1 = Temporal.PlainDateTime.from("2026-05-17T14:30:00");
const d2 = Temporal.PlainDateTime.from("2026-05-17T14:30:00");
let result = d1.equals(d2)
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Convert to ZonedDateTime
A PlainDateTime object does not include time zone information.
You can convert it to a ZonedDateTime if needed.
Example
const dateTime = Temporal.PlainDateTime.from("2026-05-17T10:00:00");
const zoned = dateTime.toZonedDateTime("Europe/Oslo");
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Temporal.PlainDateTime Methods
| Constructing | Description |
|---|---|
| from() | Creates a PlainDateTime object from an object or a string |
| new | Creates a PlainDateTime object from parameters |
| Arithmetic | |
| add() | Returns a PlainDateTime with a duration added |
| subtract() | Returns a PlainDateTime with a duration subtracted |
| round() | Returns a PlainDateTime rounded to a given unit |
| Comparing | |
| compare() | Returns -1, 0, or 1 from comparing two dates |
| equals() | Returns true if two PlainDateTime objects are identical |
| since() | Returns the difference from another PlainDateTime |
| until() | Returns the difference until another PlainDateTime |
| Converting | |
| toPlainDate() | Returns a PlainDate object with the date from this PlainDateTime |
| toPlainTime() | Returns a PlainTime object with the time from this PlainDateTime |
| toZonedDateTime() | Returns a ZonedDatetime object with this PlainDateTime in a time zone |
| with() | Returns a PlainDateTime with specified fields modified |
| withCalendar() | Returns a PlainDateTime with a different calendar system |
| withPlainTime() | Returns a PlainDateTime with the time part replaced by a new time |
| Formatting | |
| toJSON() | Returns an RFC 9557 format string for JSON serialization |
| toLocaleString() | Returns a language-sensitive representation of the date |
| toString() | Returns an RFC 9557 format string representation of the date |
| valueOf() | Throws an error to prevents temporals from being converted to primitives |
Temporal.PlainDateTime Properties
The Temporal.PlainDateTime object has 22 properties of date information.
| Property | Description |
| calendarID | Calendar system identifier ("iso8601") |
| day | The day as an integer (1-31) |
| dayOfWeek | The day of the week as an integer (1 = Monday) |
| dayOfYear | The ordinal day of the year |
| daysInMonth | The total number of days in that month |
| daysInWeek | The total number of days in that week |
| daysInYear | The total number of days in that year |
| era | The era name of the calendar, if applicable ("gregory") |
| eraYear | The year within the era, if applicable |
| hour | The hour as an integer (0-23 |
| inLeapYear | A boolean indicating if the date falls in a leap year |
| microsecond | The microsecond as an integer (0-999) |
| millisecond | The millisecond as an integer (0-999) |
| minute | The minute as an integer (0-59) |
| month | The month as an integer (1-12) |
| monthCode | A calendar-specific string code for the month ("M01") |
| monthsInYear | The total number of months in that year |
| nanosecond | The nanosecond as an integer (0-999) |
| second | The second as an integer (0-59) |
| weekOfYear | The week number within the year |
| year | The year as an integer |
| yearOfWeek | The year that the week belongs to |
Display All Properties
const date = new Temporal.PlainDateTime(2026, 5, 1, 14, 30);
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