@burglekitt/gmt/dist/utc/interval/intervalEngulfsUtc.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 true when interval B is fully contained within interval A — every instant of B
 * falls within A.
 *
 * - Uses `Temporal.Instant.compare` for comparison.
 * - Equivalent to 4-argument `intervalContainsUtc(aStart, aEnd, bStart, bEnd)`.
 * - Returns `false` if either interval is invalid (`start > end`).
 * - Returns `false` on invalid input (wrong type, malformed strings, leap seconds).
 *
 * @param aStart ISO 8601 UTC datetime string for the outer interval start
 * @param aEnd ISO 8601 UTC datetime string for the outer interval end
 * @param bStart ISO 8601 UTC datetime string for the inner interval start
 * @param bEnd ISO 8601 UTC datetime string for the inner interval end
 * @returns true if B is fully contained in A, or false on invalid input
 *
 * @example intervalEngulfsUtc("2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z", "2024-06-01T12:00:00Z", "2024-07-01T13:00:00Z") // true
 * @example intervalEngulfsUtc("2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z", "2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z") // true (equal intervals)
 * @example intervalEngulfsUtc("2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z", "2024-01-01T09:00:00Z", "2024-06-30T12:00:00Z") // true
 * @example intervalEngulfsUtc("2024-06-01T12:00:00Z", "2024-07-01T13:00:00Z", "2024-01-01T09:00:00Z", "2024-12-31T17:00:00Z") // false
 * @example intervalEngulfsUtc("invalid", "2024-12-31T17:00:00Z", "2024-06-01T12:00:00Z", "2024-07-01T13:00:00Z") // false
 */
export function intervalEngulfsUtc(aStart, aEnd, bStart, bEnd) {
    if (typeof aStart !== "string" ||
        typeof aEnd !== "string" ||
        typeof bStart !== "string" ||
        typeof bEnd !== "string") {
        return false;
    }
    if (!utcDateTime.test(aStart) ||
        !utcDateTime.test(aEnd) ||
        !utcDateTime.test(bStart) ||
        !utcDateTime.test(bEnd)) {
        return false;
    }
    if (isLeapSecond(aStart) ||
        isLeapSecond(aEnd) ||
        isLeapSecond(bStart) ||
        isLeapSecond(bEnd)) {
        return false;
    }
    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 false;
        }
        if (Temporal.Instant.compare(bS, bE) > 0) {
            return false;
        }
        return (Temporal.Instant.compare(aS, bS) <= 0 &&
            Temporal.Instant.compare(bE, aE) <= 0);
    }
    catch {
        return false;
    }
}