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@northguild/gmt

Containment and Overlap

Use these functions to answer “is this point in the range?”, “does this interval fit inside that one?”, and “do these two ranges share any time?”.

Point-in-interval (3-arg)

Section titled “Point-in-interval (3-arg)”
import {
  intervalContainsDate,
  intervalContainsTime,
  intervalContainsDateTime,
  intervalContainsUtc,
  intervalContainsUnix,
  intervalContainsZoned,
} from "@northguild/gmt";


intervalContainsDate("2024-01-01", "2024-12-31", "2024-06-15"); // true
intervalContainsTime("09:00:00", "17:00:00", "12:00:00"); // true
intervalContainsUnix(0, 1700000000, 170000000); // true

Interval-in-interval (4-arg)

Section titled “Interval-in-interval (4-arg)”
intervalContainsDate("2024-01-01", "2024-12-31", "2024-03-01", "2024-09-01"); // true

intervalEngulfs* is identical to the 4-argument intervalContains* mode — use whichever name reads better at the call site.

Overlap vs adjacency

Section titled “Overlap vs adjacency”

intervalsOverlap* returns true only when intervals share actual time. Adjacent intervals (one’s end equals the other’s start) do not overlap:

import { intervalsOverlapDate } from "@northguild/gmt";


intervalsOverlapDate("2024-01-01", "2024-06-30", "2024-04-01", "2024-12-31"); // true
intervalsOverlapDate("2024-01-01", "2024-06-30", "2024-06-30", "2024-12-31"); // false — adjacent

intervalAbuts* is the complementary check — true only when intervals touch at exactly one boundary with zero gap and zero overlap:

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


intervalAbutsDate("2024-01-01", "2024-06-30", "2024-06-30", "2024-12-31"); // true
intervalAbutsDate("2024-01-01", "2024-06-29", "2024-06-30", "2024-12-31"); // false — gap

Intersection

Section titled “Intersection”

intervalIntersection* returns the overlapping span, or null when the intervals are disjoint. Adjacent intervals count as overlapping and return a single-point span:

import { intervalIntersectionDate } from "@northguild/gmt";


intervalIntersectionDate("2024-01-01", "2024-06-30", "2024-04-01", "2024-12-31");
// { start: "2024-04-01", end: "2024-06-30" }


intervalIntersectionDate("2024-01-01", "2024-06-30", "2024-07-01", "2024-12-31");
// null — disjoint

See also

Section titled “See also”