@burglekitt/gmt/dist/plain/calculate/endOfDateTime.js

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

import { Temporal } from "@js-temporal/polyfill";
import { isValidDateTime } from "../validate/index.js";
const supported = [
    "year",
    "month",
    "week",
    "day",
    "hour",
    "minute",
    "second",
    "millisecond",
    "microsecond",
    "nanosecond",
];
/**
 * Return the end of the specified date-time `unit` for a given ISO 8601 datetime string.
 *
 * - Returns "" for invalid inputs.
 *
 * @param value ISO 8601 datetime string
 * @param unit Temporal.DateUnit | Temporal.TimeUnit to specify the unit for the end
 * @param optionsArg optional: weekStartsOn ("monday" | "sunday"), fractionalSecondDigits (number)
 * @returns ISO 8601 string representing the end of the specified unit, or "" on invalid input
 *
 * @example endOfDateTime("2024-02-29T12:34:56", "month") // "2024-02-29T23:59:59.999999999"
 * @example endOfDateTime("invalid-date", "month") // ""
 */
export function endOfDateTime(value, unit, optionsArg) {
    const weekStartsOn = optionsArg?.weekStartsOn ?? "monday";
    const fractionalSecondDigits = optionsArg?.fractionalSecondDigits;
    if (!isValidDateTime(value) || !supported.includes(unit))
        return "";
    try {
        const source = Temporal.PlainDateTime.from(value);
        let result;
        switch (unit) {
            case "year":
                result = source.with({ month: 12, day: 31 }).withPlainTime({
                    hour: 23,
                    minute: 59,
                    second: 59,
                    millisecond: 999,
                    microsecond: 999,
                    nanosecond: 999,
                });
                break;
            case "month": {
                const lastDay = Temporal.PlainDate.from({
                    year: source.year,
                    month: source.month,
                    day: 1, // Start from day 1 to get daysInMonth
                }).daysInMonth;
                result = source.with({ day: lastDay }).withPlainTime({
                    hour: 23,
                    minute: 59,
                    second: 59,
                    millisecond: 999,
                    microsecond: 999,
                    nanosecond: 999,
                });
                break;
            }
            case "week": {
                const daysToAdd = weekStartsOn === "monday"
                    ? 7 - source.dayOfWeek
                    : (6 - source.dayOfWeek) % 7;
                result = source
                    .with({ year: source.year, month: source.month, day: source.day })
                    .add({ days: daysToAdd })
                    .withPlainTime({
                    hour: 23,
                    minute: 59,
                    second: 59,
                    millisecond: 999,
                    microsecond: 999,
                    nanosecond: 999,
                });
                break;
            }
            case "day":
                result = source.withPlainTime({
                    hour: 23,
                    minute: 59,
                    second: 59,
                    millisecond: 999,
                    microsecond: 999,
                    nanosecond: 999,
                });
                break;
            case "hour":
                result = source.with({
                    minute: 59,
                    second: 59,
                    millisecond: 999,
                    microsecond: 999,
                    nanosecond: 999,
                });
                break;
            case "minute":
                result = source.with({
                    second: 59,
                    millisecond: 999,
                    microsecond: 999,
                    nanosecond: 999,
                });
                break;
            case "second":
                result = source.with({
                    millisecond: 999,
                    microsecond: 999,
                    nanosecond: 999,
                });
                break;
            case "millisecond":
                result = source.with({ microsecond: 999, nanosecond: 999 });
                break;
            case "microsecond":
                result = source.with({ nanosecond: 999 });
                break;
            case "nanosecond":
                result = source;
                break;
            default:
                return "";
        }
        // Handle default precision: 0 for > sec, 3 for ms, 6 for µs, 9 for ns
        const precisionMap = {
            millisecond: 3,
            microsecond: 6,
            nanosecond: 9,
        };
        const fractionalDigits = fractionalSecondDigits ?? (precisionMap[unit] || 0);
        return result.toString({ fractionalSecondDigits: fractionalDigits });
    }
    catch {
        return "";
    }
}