intervalAbutsDate

Signature

intervalAbutsDate(aStart: string, aEnd: string, bStart: string, bEnd: string): boolean

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

Return true when two date intervals are exactly adjacent — one’s end equals the other’s start

• with zero gap and zero overlap.
• Uses Temporal.PlainDate.compare for comparison.
• Returns true when aEnd + 1 day === bStart or bEnd + 1 day === aStart.
• Returns false when intervals overlap, are disjoint with a gap, or are invalid.
• Returns false on invalid input (wrong type, malformed strings).
• Accepts GMT calendar-annotated PlainDate strings (as produced by convertDateToCalendar) — E5 (issue #78). Comparison is by calendar-independent ordering (Temporal.PlainDate.compare ignores calendar), so the four endpoints may carry different or no calendar tags — E5 decision of record D4 (ordering-only functions accept mixed calendars).

Parameters

Parameter	Type	Description
aStart	string	ISO 8601 date string for the first interval start, optionally calendar-annotated
aEnd	string	ISO 8601 date string for the first interval end, optionally calendar-annotated
bStart	string	ISO 8601 date string for the second interval start, optionally calendar-annotated
bEnd	string	ISO 8601 date string for the second interval end, optionally calendar-annotated

Returns

true if intervals are exactly adjacent, or false on invalid input

Examples

intervalAbutsDate("2024-01-01", "2024-06-30", "2024-07-01", "2024-12-31") // true
intervalAbutsDate("2024-07-01", "2024-12-31", "2024-01-01", "2024-06-30") // true
intervalAbutsDate("2024-01-01", "2024-06-30", "2024-07-02", "2024-12-31") // false (gap)
intervalAbutsDate("2024-01-01", "2024-07-01", "2024-06-30", "2024-12-31") // false (overlap)
intervalAbutsDate("invalid", "2024-06-30", "2024-07-01", "2024-12-31") // false

Source

plain/interval/intervalAbutsDate.ts