Date Helpers

Utility functions for working with date operations.

Functions

Function	Description
add / subtract (date arithmetic)	native JS Temporal.PlainDate.prototype.add(duration) / .subtract(duration) (Temporal (Stage 3))
addDays	Adds days to a date.
addMonths	Adds months to a date.
addYears	Adds years to a date.
clampDate	Clamps a date to a [min, max] range.
compare	Comparison of two dates.
compare (ordering)	native JS Temporal.PlainDate.compare(a, b) / Temporal.Instant.compare(a, b) (Temporal (Stage 3))
daysInMonth	Returns the number of days in the given month of the given year.
difference	Calculates the difference between two dates in the specified unit.
eachDay	Returns an array of `Date` objects for each day from `start` to `end` (inclusive).
eachMonth	Returns an array of `Date` objects for the first day of each month from `start` to `end` (inclusive).
endOf	Returns a new `Date` set to the **end** of the given unit.
ensureDate	Safely converts a date-like value to a valid `Date` object, or returns `null`.
formatDuration	Formats a duration in milliseconds as a compact human-readable string.
formatInTimezone	Formats a date in a specific IANA timezone using `Intl.DateTimeFormat`.
from (parse temporal string)	native JS Temporal.Instant.from(str) / Temporal.PlainDate.from(str) / etc. (Temporal (Stage 3))
fromMillis	Creates a `Date` from a timestamp in **milliseconds**.
fromSeconds	Creates a `Date` from a timestamp in **seconds**.
getTimezoneOffset	Returns the UTC offset **in minutes** for the given IANA timezone at a specific point in time.
isBusinessDay	Checks whether a date falls on a business day (i.e.
isLeapYear	Returns `true` if the given year is a leap year.
isSameDay	Checks if two dates are the same day.
isSameMonth	Checks if two dates are in the same month (and year).
isSameYear	Checks if two dates are in the same year.
isTimestampInSeconds	Checks if a timestamp is likely in seconds (Java/Unix style) vs milliseconds (JavaScript style)
isValid	Checks if a value is a valid Date instance (not `Invalid Date`).
isValidDateString	Checks whether a string can be parsed into a valid `Date`.
isWeekend	Checks whether a date falls on a weekend day.
isWithinRange	Checks whether a date falls within a range (inclusive on both ends).
listTimezones	Returns the list of IANA timezone identifiers supported by the runtime.
normalizeTimestamp	Converts a timestamp to JavaScript milliseconds format
now (date/time/instant)	native JS Temporal.Now.instant() / .zonedDateTimeISO() / .plainDateISO() / .plainTimeISO() (Temporal (Stage 3))
overlaps	Checks whether two date ranges overlap.
parseDuration	Parses a compact duration string (as produced by formatDuration, e.g.
startOf	Returns a new `Date` set to the **start** of the given unit.
timeAgo	Formats a date as a human-readable relative time string.
toISO8601	Converts a date to ISO 8601 format Format: YYYY-MM-DDTHH:mm:ss.sssZ
toMillis	Converts a date to a timestamp in **milliseconds** (epoch millis).
toPlainDate / toPlainDateTime / toPlainTime	native JS Temporal.ZonedDateTime.prototype.toPlainDate() / toPlainDateTime() / toPlainTime() (Temporal (Stage 3))
toRFC2822	Converts a date to RFC 2822 format Format: Day, DD Mon YYYY HH:mm:ss +0000 Used in email headers (Date field) and HTTP …
toRFC3339	Converts a date to RFC 3339 format Format: YYYY-MM-DDTHH:mm:ssZ or YYYY-MM-DDTHH:mm:ss+HH:mm RFC 3339 is a profile of I…
toSeconds	Converts a date to a timestamp in **seconds** (epoch seconds).
toTemporalInstant	native JS Date.prototype.toTemporalInstant() (Temporal (Stage 3))
toZonedDateTime	native JS Temporal.Instant.prototype.toZonedDateTimeISO(tz) (Temporal (Stage 3))
until / since (difference)	native JS Temporal.PlainDate.prototype.until(other) / .since(other) (Temporal (Stage 3))
WeekDays	Named day-of-week constants following the JavaScript `Date.getDay()` convention.