endOfDateTime

Signature

endOfDateTime(value: string, unit: SmallestUnit<DateTimeUnit>, optionsArg?: { weekStartsOn?: "monday" | "sunday"; fractionalSecondDigits?: FractionalDigit; }): string

Return the end of the specified date-time unit for a given ISO 8601 datetime string.

• The end is computed forward from value, so it is returned even when the unit began before the first representable date (-271821-04-19).
• unit accepts the singular or plural name ("month" or "months"), as Temporal does.
• Returns "" for invalid inputs.
• Compatibility: before 1.16.0 the default printed only the digits the unit names — none for second and coarser, 3 for millisecond, 6 for microsecond — which wrote a moment earlier than the end. Pass that fractionalSecondDigits to keep the previous string.

Parameters

Parameter	Type	Description
value	string	ISO 8601 datetime string
unit	SmallestUnit<DateTimeUnit>	date or time unit, singular or plural, to specify the unit for the end

Options

optionsArg

How the week is defined and how the result is written

Option	Type	Default	Description
weekStartsOn?	"monday" | "sunday"	"monday"	The first day of the week, which sets where a "week" unit starts. "monday" is the ISO 8601 week, Monday to Sunday; "sunday" runs Sunday to Saturday. Any other value returns "", whatever the unit.
fractionalSecondDigits?	0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | "auto" | 8 | 9 (FractionalDigit)	9	The number of fractional-second digits the result is written with, 0 to 9, or "auto" to drop trailing zeros. Fewer than 9 digits truncate the string, as Temporal’s toString does, so it names a moment before the end.

Returns

ISO 8601 string representing the end of the specified unit, or "" on invalid input

Related types

• FractionalDigit

Examples

import { endOfDateTime } from "@northguild/gmt/plain/calculate";

endOfDateTime("2024-02-29T12:34:56", "month") // "2024-02-29T23:59:59.999999999"

value

output

 

Source

plain/calculate/endOfDateTime.ts