@burglekitt/gmt/dist/plain/interval/intervalAbutsDateTime.js

Temporal-based date and time utilities with timezone support and polyfill integration

import { Temporal } from "@js-temporal/polyfill";
import { plainDateTime } from "../../regex/index.js";
/**
 * Return true when two datetime intervals are exactly adjacent — one's end equals the other's
 * start with zero gap and zero overlap.
 *
 * - Uses `Temporal.PlainDateTime.compare` for comparison.
 * - Returns `true` when `aEnd + 1 nanosecond === bStart` or `bEnd + 1 nanosecond === aStart`.
 * - Returns `false` when intervals overlap, are disjoint with a gap, or are invalid.
 * - Returns `false` on invalid input (wrong type, malformed strings).
 *
 * @param aStart ISO 8601 datetime string for the first interval start
 * @param aEnd ISO 8601 datetime string for the first interval end
 * @param bStart ISO 8601 datetime string for the second interval start
 * @param bEnd ISO 8601 datetime string for the second interval end
 * @returns true if intervals are exactly adjacent, or false on invalid input
 *
 * @example intervalAbutsDateTime("2024-01-01T09:00:00", "2024-06-30T12:00:00", "2024-06-30T12:00:00.000000001", "2024-12-31T17:00:00") // true
 * @example intervalAbutsDateTime("2024-06-30T12:00:00", "2024-12-31T17:00:00", "2024-01-01T09:00:00", "2024-06-30T12:00:00.000000001") // true
 * @example intervalAbutsDateTime("2024-01-01T09:00:00", "2024-06-30T12:00:00", "2024-06-30T12:00:01", "2024-12-31T17:00:00") // false (gap)
 * @example intervalAbutsDateTime("2024-01-01T09:00:00", "2024-06-30T13:00:00", "2024-06-30T12:00:00", "2024-12-31T17:00:00") // false (overlap)
 * @example intervalAbutsDateTime("invalid", "2024-06-30T12:00:00", "2024-06-30T12:00:00", "2024-12-31T17:00:00") // false
 */
export function intervalAbutsDateTime(aStart, aEnd, bStart, bEnd) {
    if (typeof aStart !== "string" ||
        typeof aEnd !== "string" ||
        typeof bStart !== "string" ||
        typeof bEnd !== "string") {
        return false;
    }
    if (!plainDateTime.test(aStart) ||
        !plainDateTime.test(aEnd) ||
        !plainDateTime.test(bStart) ||
        !plainDateTime.test(bEnd)) {
        return false;
    }
    try {
        const aS = Temporal.PlainDateTime.from(aStart);
        const aE = Temporal.PlainDateTime.from(aEnd);
        const bS = Temporal.PlainDateTime.from(bStart);
        const bE = Temporal.PlainDateTime.from(bEnd);
        if (Temporal.PlainDateTime.compare(aS, aE) > 0) {
            return false;
        }
        if (Temporal.PlainDateTime.compare(bS, bE) > 0) {
            return false;
        }
        // aEnd + 1 nanosecond === bStart
        const aEndPlusOne = aE.add({ nanoseconds: 1 });
        if (Temporal.PlainDateTime.compare(aEndPlusOne, bS) === 0) {
            return true;
        }
        // bEnd + 1 nanosecond === aStart
        const bEndPlusOne = bE.add({ nanoseconds: 1 });
        if (Temporal.PlainDateTime.compare(bEndPlusOne, aS) === 0) {
            return true;
        }
        return false;
    }
    catch {
        return false;
    }
}