intervalContainsDate

Signature

intervalContainsDate(intervalStart: string, intervalEnd: string, pointOrStart: string, pointEnd?: string): boolean

Return true when pointOrStart lies in the half-open interval [intervalStart, intervalEnd) (3-arg), or when the inner interval [innerStart, innerEnd) lies within it (4-arg).

• Half-open: an interval holds every day t with start <= t < end, so intervalEnd itself is outside (the rule CORE-6’s intervalContains uses). An empty interval (start === end) contains no point.
• 4-arg: the inner interval must start at or after intervalStart, end at or before intervalEnd, and overlap the outer interval. An empty inner interval therefore counts only strictly inside, never at an edge (CORE-6’s clampInterval clamps it away there).
• Uses Temporal.PlainDate.compare for comparison.
• Returns false if intervalStart > intervalEnd (invalid outer interval).
• Returns false if innerStart > innerEnd in 4-arg mode (invalid inner interval).
• Returns false on invalid input (wrong type, malformed strings).
• Accepts RFC 9557 calendar-annotated PlainDate strings — E5 (issue #78). Ordering is calendar-independent, so arguments may carry different or no calendar tags (D4).
• Compatibility: since 1.16.0 calendar strings are RFC 9557 (ISO digits, [u-ca=<id>], canonical calendar ids); see isValidCalendarDate.

Parameters

Parameter	Type	Description
intervalStart	string	ISO 8601 date string for the outer interval start, optionally calendar-annotated
intervalEnd	string	ISO 8601 date string for the outer interval end (excluded), optionally calendar-annotated
pointOrStart	string	ISO 8601 date string for the point (3-arg) or inner start (4-arg), optionally calendar-annotated
pointEnd	string	optional ISO 8601 date string for the inner interval end (4-arg mode), optionally calendar-annotated

Returns

true if the point or inner interval is contained, or false on invalid input

Examples

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

intervalContainsDate("2024-01-01", "2024-12-31", "2024-06-15") // true

intervalStartintervalEndpointOrStartpointEnd ?

output

 

Source

plain/interval/intervalContainsDate.ts