timeToCutoff

Signature

timeToCutoff(now: string, cutoff: string): string

Measure the time left until a cut-off, negative once it has passed.

• Exact elapsed time as an ISO 8601 duration with hours as the largest unit, so the value never depends on a calendar: across a fall-back night, 17:00 to 17:00 the next day is PT25H. It is PT0S at the cut-off itself, where isPastCutoff turns true.
• Negative ("-PT1H") once now is after the cut-off: how late it is.
• Both arguments are exact: an instant (Z/offset) or a zoned string, as cutoffAt returns one. The zone each is written in does not matter.
• The offset fixes the instant; a bracketed zone only resolves a rounded one. An offset written to the minute that is the bracketed zone’s sub-minute offset rounded (-00:45[Africa/Monrovia], for −00:44:30) names the instant the zone gives, as Temporal.ZonedDateTime.from reads it, so a cut-off cutoffAt wrote is the instant it computed, except a wall time repeated inside a sub-minute offset change, which reads as its first pass (see isValidInstant). Otherwise the bracket is not checked: a zone that does not exist, or that disagrees with the offset, changes nothing.
• now is the caller’s: GMT does not read the clock here.
• Returns "" on invalid input, including cutoffAt’s "" sentinel.

Parameters

Parameter	Type	Description
now	string	ISO 8601 instant or zoned datetime string of the moment asked about
cutoff	string	ISO 8601 instant or zoned datetime string of the cut-off

Returns

ISO 8601 duration from now to the cut-off, negative after it, or "" on invalid input

Examples

import { timeToCutoff } from "@northguild/gmt/transport/compare";

timeToCutoff("2024-06-10T15:00:00Z", "2024-06-12T17:00:00+02:00[Europe/Amsterdam]") // "PT48H"

nowcutoff

output

 

Source

transport/compare/timeToCutoff.ts