@burglekitt/gmt/dist/utc/interval/intervalXorUtc.js

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

import { Temporal } from "@js-temporal/polyfill";
import { isLeapSecond } from "../../plain/validate/isLeapSecond.js";
import { utcDateTime } from "../../regex/utc-date-time.js";
/**
 * Return the symmetric difference of two UTC intervals — time covered by exactly one interval.
 *
 * - Uses `Temporal.Instant.compare` for comparison.
 * - Returns `[]` when intervals are identical or both invalid.
 * - Returns `[{ start, end }]` when one interval fully contains the other.
 * - Returns `[{ start, end }, { start, end }]` when intervals partially overlap.
 * - Returns `[]` if either interval is invalid (`start > end`).
 * - Returns `[]` on invalid input (wrong type, malformed strings, leap seconds).
 *
 * @param aStart ISO 8601 UTC datetime string for the first interval start
 * @param aEnd ISO 8601 UTC datetime string for the first interval end
 * @param bStart ISO 8601 UTC datetime string for the second interval start
 * @param bEnd ISO 8601 UTC datetime string for the second interval end
 * @returns array of `{ start, end }` records representing the symmetric difference, or `[]` on invalid input
 *
 * @example intervalXorUtc("2024-01-01T09:00:00Z", "2024-06-30T12:00:00Z", "2024-04-01T11:00:00Z", "2024-12-31T17:00:00Z") // [{ start: "2024-01-01T09:00:00Z", end: "2024-03-31T17:00:00Z" }, { start: "2024-06-30T12:00:01Z", end: "2024-12-31T17:00:00Z" }]
 * @example intervalXorUtc("2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z", "2024-04-01T11:00:00Z", "2024-06-30T12:00:00Z") // [{ start: "2024-01-01T09:00:00Z", end: "2024-03-31T17:00:00Z" }, { start: "2024-06-30T12:00:01Z", end: "2024-12-31T17:00:00Z" }]
 * @example intervalXorUtc("2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z", "2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z") // []
 * @example intervalXorUtc("invalid", "2024-06-30T12:00:00Z", "2024-07-01T13:00:00Z", "2024-12-31T17:00:00Z") // []
 */
export function intervalXorUtc(aStart, aEnd, bStart, bEnd) {
    if (typeof aStart !== "string" ||
        typeof aEnd !== "string" ||
        typeof bStart !== "string" ||
        typeof bEnd !== "string") {
        return [];
    }
    if (!utcDateTime.test(aStart) ||
        !utcDateTime.test(aEnd) ||
        !utcDateTime.test(bStart) ||
        !utcDateTime.test(bEnd)) {
        return [];
    }
    if (isLeapSecond(aStart) ||
        isLeapSecond(aEnd) ||
        isLeapSecond(bStart) ||
        isLeapSecond(bEnd)) {
        return [];
    }
    try {
        const aS = Temporal.Instant.from(aStart);
        const aE = Temporal.Instant.from(aEnd);
        const bS = Temporal.Instant.from(bStart);
        const bE = Temporal.Instant.from(bEnd);
        if (Temporal.Instant.compare(aS, aE) > 0) {
            return [];
        }
        if (Temporal.Instant.compare(bS, bE) > 0) {
            return [];
        }
        const result = [];
        // If intervals don't overlap, return both as-is
        if (Temporal.Instant.compare(aE, bS) < 0 ||
            Temporal.Instant.compare(bE, aS) < 0) {
            return [
                { start: aS.toString(), end: aE.toString() },
                { start: bS.toString(), end: bE.toString() },
            ];
        }
        // Left piece: A before B starts
        if (Temporal.Instant.compare(aS, bS) < 0) {
            result.push({
                start: aS.toString(),
                end: bS.subtract({ nanoseconds: 1 }).toString(),
            });
        }
        // Right piece: A after B ends
        if (Temporal.Instant.compare(aE, bE) > 0) {
            result.push({
                start: bE.add({ nanoseconds: 1 }).toString(),
                end: aE.toString(),
            });
        }
        // Left piece: B before A starts
        if (Temporal.Instant.compare(bS, aS) < 0) {
            result.push({
                start: bS.toString(),
                end: aS.subtract({ nanoseconds: 1 }).toString(),
            });
        }
        // Right piece: B after A ends
        if (Temporal.Instant.compare(bE, aE) > 0) {
            result.push({
                start: aE.add({ nanoseconds: 1 }).toString(),
                end: bE.toString(),
            });
        }
        return result;
    }
    catch {
        return [];
    }
}