diffZonedAsDuration

Signature

diffZonedAsDuration(value1: string, value2: string, unit: keyof DurationLike | DateTimeUnit, options?: (RoundingOptions<DateTimeUnit> & DurationStringOptions)): string

Return the difference between two zoned datetimes as an ISO 8601 duration string, bridging to the duration namespace (see parseDuration, normalizeDuration).

• Uses Temporal.ZonedDateTime.until with largestUnit set to unit, then .toString().
• Measures like diffZoned (Temporal’s DifferenceZonedDateTime): calendar units on the zone’s own wall clock, time units in exact elapsed time. Values in different time zones with a calendar unit (days or larger) return "".
• Compatibility: before 1.16.0 both values were converted to UTC first. To get that value: diffUtcAsDuration(convertZonedToUtc(value1), convertZonedToUtc(value2), unit).
• Accepts RFC 9557 calendar-annotated zoned strings, with the same calendar rule as diffZoned: measured in the shared calendar, "" when the two name different calendars (TC39 CalendarEquals; before 1.16.0 measured in ISO).
• Unlike diffZoned, unit is a single unit (not an array) — an ISO duration string already expresses a full multi-unit breakdown via largestUnit alone, so there’s no array-of-units overload here.
• Returns "" for invalid input (negative diffs are valid and render with a leading -). smallestUnit, roundingIncrement, and roundingMode control optional rounding of the underlying difference before it’s rendered, per Temporal’s DifferenceOptions — same as diffZoned. toStringSmallestUnit, fractionalSecondDigits, and toStringRoundingMode control the precision of the rendered string itself, per Temporal’s ToStringPrecisionOptions (mirroring parseDuration’s options) — kept separate from the .until() rounding options above because both option sets have colliding smallestUnit/roundingMode keys with different Temporal types.
• Compatibility: since 1.16.0 calendar strings are RFC 9557 (ISO digits, the [u-ca=<id>] annotation after the zone, canonical calendar ids); see isValidCalendarZonedDateTime.

Parameters

Parameter	Type	Description
value1	string	zoned ISO 8601 datetime string (start), optionally calendar-annotated
value2	string	zoned ISO 8601 datetime string (end), optionally calendar-annotated
unit	keyof DurationLike | DateTimeUnit	date-time unit to use as the duration’s largestUnit, singular or plural ("day" or "days")

Options

options

optional: how the difference is rounded and how the string is rendered; a non-object value (such as null) is invalid

Option	Type	Default	Description
smallestUnit?	DateTimeUnit | PluralUnit<DateTimeUnit>	None. The difference is not rounded: Temporal uses the smallest unit the values have, "day" for dates and "nanosecond" otherwise.	The smallest unit kept in the difference; anything smaller is rounded into it. It may not be larger than the largest unit asked for.
roundingIncrement?	number	1, Temporal’s default.	The step the smallest unit is rounded to, so 15 with "minute" rounds to a quarter of an hour. For a time unit it must divide the next larger unit evenly and be smaller than it (15 or 30 minutes, not 7 or 60); a date unit takes any whole number from 1 up. A non-integer is truncated first, as Temporal does, and any other value is invalid input.
roundingMode?	"ceil" | "floor" | "expand" | "trunc" | "halfCeil" | "halfFloor" | "halfExpand" | "halfTrunc" | "halfEven"	"trunc", Temporal’s default for a difference.	Which way a value between two steps goes. "trunc" rounds toward zero and "halfExpand" to the nearest step, a half going away from zero; the other modes are those of Temporal’s roundingMode option.
toStringSmallestUnit?	SmallestUnit<"minute" | "second" | "millisecond" | "microsecond" | "nanosecond">	None. The precision comes from fractionalSecondDigits.	The smallest unit written in the string: "second", "millisecond", "microsecond" or "nanosecond". It sets how many fractional-second digits appear and takes precedence over fractionalSecondDigits. "minute" is refused, as Temporal.Duration refuses it.
fractionalSecondDigits?	0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | "auto" | 8 | 9	"auto", Temporal’s default.	The number of fractional-second digits written: 0 to 9 writes exactly that many, and "auto" writes as many as the duration needs, with no trailing zeros. It has no effect when toStringSmallestUnit is given.
toStringRoundingMode?	RoundingMode	"trunc", Temporal’s default.	How the duration is rounded when the precision asked for drops digits. "trunc" cuts them off; "halfExpand" rounds to the nearest value, a half going away from zero.

Returns

ISO 8601 duration string, or "" on invalid input

Related types

• DateTimeDurationUnit
• RoundingOptions
• DurationStringOptions

Examples

import { diffZonedAsDuration } from "@northguild/gmt/zoned/calculate";

diffZonedAsDuration("2024-03-09T12:00:00-05:00[America/New_York]", "2024-03-11T12:00:00-04:00[America/New_York]", "days") // "P2D" (wall-clock days; 47 elapsed hours)

value1value2

output

 

Source

zoned/calculate/diffZonedAsDuration.ts