vremel/dist/datetime/fromRfc2822.js

JavaScript date utility library for Temporal API

import { isInstantConstructor, isPlainDateTimeConstructor, } from "../type-utils.js";
import { createRecord } from "./_createRecord.js";
import { formatExactTimeIso } from "./_formatExactTimeIso.js";
import { getDayOfWeekFromYmd } from "./_getDayOfWeekFromYmd.js";
import { getDayOfWeekNumberFromAbbreviation } from "./_getDayOfWeekNumberFromAbbreviation.js";
import { getMonthNumberFromAbbreviation } from "./_getMonthNumberFromAbbreviation.js";
// spec: https://datatracker.ietf.org/doc/html/rfc2822#section-3.3 https://datatracker.ietf.org/doc/html/rfc2822#section-4.3
function removeComment(str) {
    const r = /(?<!\\)[()]/g;
    let res = "";
    let commentNestLevel = 0;
    let lastNonCommentStarted = 0;
    for (const m of str.matchAll(r)) {
        if (m[0] === "(") {
            if (commentNestLevel === 0) {
                // comment started
                res += str.slice(lastNonCommentStarted, m.index);
            }
            commentNestLevel++;
        }
        else {
            commentNestLevel--;
            if (commentNestLevel === 0) {
                // comment ended
                lastNonCommentStarted = m.index + 1;
            }
            if (commentNestLevel < 0) {
                throw new Error("Unbalanced nested comment");
            }
        }
    }
    if (commentNestLevel !== 0) {
        throw new Error("Unbalanced nested comment");
    }
    return res;
}
const dateTimeFormatRegex = /^[ \t\r\n]*(?:([A-Za-z]{3}),)?[ \t\r\n]*(\d\d)[ \t\r\n]+([A-Za-z]{3})[ \t\r\n]+(\d\d|\d\d\d\d)[ \t\r\n]+(\d\d):(\d\d)(?::(\d\d))?[ \t\r\n]+([+-]\d{4}|[A-Za-z]+)[ \t\r\n]*$/;
function fullYear(year) {
    const yearNum = parseInt(year, 10);
    if (year.length === 4) {
        return yearNum;
    }
    return yearNum >= 50 ? 1900 + yearNum : 2000 + yearNum;
}
function getOffset(timeZone) {
    if (["UT", "GMT", "z", "Z"].includes(timeZone)) {
        return "+00:00";
    }
    if (timeZone === "-0000" || /^[A-IK-Za-ik-z]$/.test(timeZone)) {
        // according to the spec, military zone except 'Z' should be considered equivalent to "-0000",
        // which means the date-time contains no information about the local time zone
        throw new Error("No offset info");
    }
    if (/^[+-]\d{4}$/.test(timeZone)) {
        return `${timeZone.slice(0, 3)}:${timeZone.slice(3)}`;
    }
    const table = createRecord({
        EDT: "-04:00",
        EST: "-05:00",
        CDT: "-05:00",
        CST: "-06:00",
        MDT: "-06:00",
        MST: "-07:00",
        PDT: "-07:00",
        PST: "-08:00",
    });
    if (table[timeZone] !== undefined) {
        return table[timeZone];
    }
    throw new Error("Unknown time zone");
}
function parse(date) {
    const result = dateTimeFormatRegex.exec(date);
    if (result === null) {
        throw new Error(`Invalid date and time format: ${date}`);
    }
    const [, dayOfWeek, day, monthName, year, hour, minute, second = "00", timeZone,] = result;
    if (day === undefined ||
        monthName === undefined ||
        year === undefined ||
        hour === undefined ||
        minute === undefined ||
        timeZone === undefined) {
        throw new Error("something wrong");
    }
    return [
        fullYear(year),
        getMonthNumberFromAbbreviation(monthName),
        parseInt(day),
        parseInt(hour, 10),
        parseInt(minute, 10),
        parseInt(second),
        dayOfWeek,
        timeZone,
    ];
}
/**
 * Creates Temporal object from datetime string in RFC 2822's format.
 *
 * @param date datetime string in RFC 2822's format
 * @param TemporalClass Temporal class (such as `Temporal.PlainDateTime` or `Temporal.Instant`) which will be returned
 * @returns an instance of Temporal class specified in `TemporalClass` argument
 */
export function fromRfc2822(date, TemporalClass) {
    const dateWithoutComment = date.includes("(") ? removeComment(date) : date;
    const [year, month, day, hour, minute, second, dayOfWeek, timeZone] = parse(dateWithoutComment);
    if (dayOfWeek !== undefined &&
        getDayOfWeekFromYmd(year, month, day) !==
            getDayOfWeekNumberFromAbbreviation(dayOfWeek)) {
        throw new Error(`Wrong day of week: ${dayOfWeek}`);
    }
    if (isPlainDateTimeConstructor(TemporalClass)) {
        return TemporalClass.from({
            year,
            month,
            day,
            hour,
            minute,
            second,
            calendarId: "iso8601",
        });
    }
    const offsetIso = getOffset(timeZone);
    if (isInstantConstructor(TemporalClass)) {
        return TemporalClass.from(formatExactTimeIso(year, month, day, hour, minute, second, 0, offsetIso));
    }
    return TemporalClass.from({
        year,
        month,
        day,
        hour,
        minute,
        second,
        calendarId: "iso8601",
        timeZone: offsetIso,
    });
}
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