intervalXorAllDate

Signature

intervalXorAllDate(intervals: { start: string; end: string; }[]): { start: string; end: string; }[]

import { intervalXorAllDate } from "@northguild/gmt/plain/interval";

Return the symmetric difference across a list of date intervals — the set of dates covered

• by an odd number of the input intervals.
• List-form generalization of intervalXorDate, which is pairwise only.
• Implemented as a coverage sweep: each interval contributes a +1 at its start and a -1 the day after its end; the result is every maximal run where the running coverage count is odd. For two intervals this reduces to exactly intervalXorDate’s pairwise result.
• Order of the input list does not matter; the result is sorted by start.
• Returns [] for an empty list, and [] when every date is covered an even number of times (e.g. two identical intervals cancel out).
• Returns [] when intervals is not an array, when any element is not a { start, end } record of valid ISO PlainDate strings, or when any element has start > end.
• Accepts GMT calendar-annotated PlainDate strings — E5 (issue #78). Since the result is date values, every start/end across the whole list must carry the same calendar tag (or all be bare ISO); any mismatch returns [] (E5 decision of record D4). This also makes .equals()’s dedup of coincident sweep events safe — same-calendar PlainDates compare equal correctly, unlike cross-calendar ones.

Parameters

Parameter	Type	Description
intervals	{ start: string; end: string; }[]	array of { start, end } records, optionally calendar-annotated

Returns

array of { start, end } records covered an odd number of times, or [] on invalid input / mismatched calendars

Examples

intervalXorAllDate([{ start: "2024-01-01", end: "2024-01-10" }, { start: "2024-01-05", end: "2024-01-15" }, { start: "2024-01-08", end: "2024-01-20" }]) // [{ start: "2024-01-01", end: "2024-01-04" }, { start: "2024-01-08", end: "2024-01-10" }, { start: "2024-01-16", end: "2024-01-20" }]
intervalXorAllDate([{ start: "2024-01-01", end: "2024-01-05" }, { start: "2024-01-01", end: "2024-01-05" }]) // [] (identical intervals cancel out)
intervalXorAllDate([]) // []
intervalXorAllDate([{ start: "2024-01-10", end: "2024-01-01" }]) // []

Source

plain/interval/intervalXorAllDate.ts