javascript - 如何在没有外部库或复杂天文方程的 Javascript 中将波斯 (Jalali) 日期转换为其他 18 个日历日期

Question

TL;DR, 要求能够采用波斯(Jalali)日期(也称为波斯太阳回历)，如 Esfand 19, 1400(即 "12/19/1400")并将其转换为其他日历(公历、伊斯兰、中国、希伯来等) .) 不使用外部库或复杂的天文方程 。并且不使用新日期 Temporal API 到 Javascript 中的未决实现。
Javascript 内置方法 Intl.DateTimeFormat() 将公历日期转换为各种日历的日期(18 个世界日历)，包括输出字符串的格式。
但是，截至今天(2022 年 3 月)，Javascript 没有提供用于反向操作的内置方法，即将波斯日期(和其他日历的日期)转换回公历日期或其他日历。为此，您将需要使用外部日期库进行转换，例如“moment.js”等。
我的日期转换方法如下作为 StackOverflow 推荐的此问题的答案:Can I answer my own question?

Answer 1

下面的简短 Javascript 函数不 使用外部库并提供工具将波斯 (Jalali) 日期( 从波斯年 -272,442 AP 到 +275,139 AP )转换为以下 18 个 Javascript 日历中的任何一个，并带有用于格式化结果输出的选项:"buddhist", "chinese", "coptic", "dangi", "ethioaa", "ethiopic", "gregory", "hebrew", "indian", "islamic", "islamic-umalqura", "islamic-tbla", "islamic-civil", "islamic-rgsa", "iso8601", "japanese", "persian", "roc", "islamicc".该方法也不使用复杂的数学或天文公式，仅依赖于 Javascript 内置日历转换算法，而这些算法又基于 ICU 代码 [https://icu.unicode.org/]。
这种方法可确保输出始终准确并完全符合 Javascript 引擎输出。
句法

persianToCalendars(year, month, day, [options])

在其最简单的形式中，该函数默认将波斯日期转换为 Gregorian使用 ISO 日期格式的日历。
示例:将波斯日期 Esfand 19、1400(即 12/19/1400)转换为公历。

persianToCalendars(1400,12,19);

output: 2022-03-10T00:00:00.000Z    // default output Gregorian ISO format

要将波斯日期转换为另一个日历(例如“伊斯兰”日历):

 persianToCalendars(1400,12,19, { toCal: "islamic-umalqura" });

 output: 8/7/1443 AH

要为输出添加格式，请使用 'dateStyle' Javascript 中的选项 Intl.DateTimeFormat()方法。
示例:使用完整的 dateStyle 将波斯日期转换为伊斯兰日期

 persianToCalendars(1400,12,19, { toCal: "islamic-umalqura", dateStyle: "full" });

 output: Thursday, Shaʻban 7, 1443 AH

示例:将波斯语日期转换为带有波斯语语言环境的希伯来语

 persianToCalendars(1400,12,19, { toCal:"hebrew", dateStyle: "full", locale:"fa"})

 output: پنجشنبه ۷ واذار الثانی ۵۷۸۲ تقویم عبری

以上可以为所有其他 18 个日历完成。
一个附加功能是能够将波斯日期格式化为任何可用的 'dateStyles'和 'locales' 无转换 .
为此，请指定 'toCal'至 persian 示例:使用波斯语区域设置格式化波斯日期

 persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"fa"}));

 output:  ۱۴۰۰ اسفند ۱۹, پنجشنبه         // mind the RTL requirements

示例:在印地语语言环境中格式化波斯日期

 persianToCalendars(1400,12,19,{ toCal : "persian", dateStyle : "full", locale : "hi"}));

 output: AP गुरुवार, 19 ईस्फन्द् 1400

您可以使用 Intl.DateTimeFormat() 中提供的所有选项。用于格式化输出日期。
无效的波斯日期
如果将无效的伊斯兰日期传递给函数，则会出现错误 Invalid Persian Date!会生成。
无效的波斯日期是指月份中日期不正确或日期或月份不正确的日期。
例如，波斯日期 1400/12/30 无效，因为波斯历的第 12 个月(“Esfand”月)是 1400 年的 29 天。
future 的Javascript Temporal API将使这项任务更简单。

/*********************************************************************
* @function  : persianToCalendars(year, month, day, [options])
*
* @purpose   : Converts Persian/Iranian Date (Jalali Date) to the corresponding Gregorian Date.
*              Handles Persian dates from -272,442 AP to +275,139 AP.
*              Uses the 'JS Calendar Conversion by Target Approximation' Method.
*              No external libraries or complex mathematical/astronautical formulas.
*
* @version   : 1.00
* @author    : Mohsen Alyafei
* @date      : 17 Feb 2022
* @licence   : MIT
* @param     : year  : (numeric) Persian year  (-272442 to 275139)
* @param     : month : (numeric) Persian month (1 to 12) note: months is standard 1 based
* @param     : day   : (numeric) Persian day   (1 to 31)
* @param     : options: Object with the following optional parameters:
*
*              'toCal' : Specifies the the type of output Calendar to convert to with 18 Calendars:
*                        - "gregory" : (default)
*                        - "buddhist", "chinese", "coptic", "dangi", "ethioaa", "ethiopic",
*                          "hebrew", "indian", "islamic", "islamic-umalqura", "islamic-tbla",
*                          "islamic-civil", "islamic-rgsa", "iso8601", "japanese", "persian", "roc".
*
*               'dateStyle' Same as used in the Intl.DateTimeFormat() constructor.
*                           If not stated, default output is in Gregorian ISO Format: YYYY:MM:DDTHH:mm:ss.sssZ
*
*               'locale' The BCP 47 language tag for formatting (default is 'en'). If the 'locale'
*                        is given then no date conversion happens and the Persian date is formatted
*                        based on the specified 'dateStyle' and 'locale'.
*
*               Other options: As used in the Intl.DateTimeFormat() constructor.
*
* @returns   : Return the date in the calendar and format of the specified 'options'
**********************************************************************/




//==========================================================
function persianToCalendars(year, month, day, op={}) {
const formatOut= gD=> "toCal"in op?(op.calendar=op.toCal,new Intl.DateTimeFormat(op.locale??"en",op).format(gD)):gD,
      dFormat  = new Intl.DateTimeFormat('en-u-ca-persian',{dateStyle:'short',timeZone:"UTC"});
let   gD       = new Date(Date.UTC(2000,month,day));
      gD       = new Date(gD.setUTCDate(gD.getUTCDate() + 226867));
const gY       = gD.getUTCFullYear()-2000+year;
      gD       = new Date(((gY<0)?"-":"+")+("00000"+Math.abs(gY)).slice(-6)+"-"+("0"+(gD.getUTCMonth()+1)).slice(-2)+"-"+("0"+(gD.getUTCDate())).slice(-2));
let [pM,pD,pY] = [...dFormat.format(gD).split("/")], i=0;
      gD       = new Date(gD.setUTCDate(gD.getUTCDate() +
                 ~~(year*365.25+month*30.44+day-(pY.split(" ")[0]*365.25+pM*30.44+pD*1))-2));
while (i < 4) {
    [pM,pD,pY]=[...dFormat.format(gD).split("/")];
    if (pD==day && pM==month && pY.split(" ")[0]==year) return formatOut(gD);
    gD = new Date(gD.setUTCDate(gD.getUTCDate()+1));i++;
}
throw new Error('Invalid Persian Date!');
}
//==========================================================










//==========================================================
// Test Units
//==========================================================
console.log("-".repeat(55));
console.log("Convert the Persian Date '1400-12-19' to other calendars:");
console.log("input to function: persianToCalendars(1400,12,19, options)");
console.log("-".repeat(55));

console.log("Default (Gregory) ISO format   : ",persianToCalendars(1400,12,19)); // convert to default gregorian date
console.log("Gregory 'full' format          : ",persianToCalendars(1400,12,19,{toCal:"gregory",dateStyle:"full"}));
console.log("Islamic 'full' format          : ",persianToCalendars(1400,12,19,{toCal:"islamic",dateStyle:"full"}));
console.log("Islamic-Umaalqura 'short'format: ",persianToCalendars(1400,12,19,{toCal:"islamic-umalqura"}));
console.log("Islamic-Umaalqura 'full' format: ",persianToCalendars(1400,12,19,{toCal:"islamic-umalqura",dateStyle:"full"}));
console.log("Islamic-civil 'full' format    : ",persianToCalendars(1400,12,19,{toCal:"islamic-civil",dateStyle:"full"}));
console.log("Islamic-tbla 'full' format     : ",persianToCalendars(1400,12,19,{toCal:"islamic-tbla",dateStyle:"full"}));
console.log("Islamic-rgsa 'full' format     : ",persianToCalendars(1400,12,19,{toCal:"islamic-rgsa",dateStyle:"full"}));
console.log("Hebrew 'full' format           : ",persianToCalendars(1400,12,19,{toCal:"hebrew",dateStyle:"full"}));
console.log("Indian 'full' format           : ",persianToCalendars(1400,12,19,{toCal:"indian",dateStyle:"full"}));
console.log("Buddhist 'full' format         : ",persianToCalendars(1400,12,19,{toCal:"buddhist",dateStyle:"full"}));
console.log("Chinese 'full' format          : ",persianToCalendars(1400,12,19,{toCal:"chinese",dateStyle:"full"}));
console.log("Dangi (Korean) 'full' format   : ",persianToCalendars(1400,12,19,{toCal:"dangi",dateStyle:"full"}));
console.log("R.O.C. (Minguo) 'full' format  : ",persianToCalendars(1400,12,19,{toCal:"roc",dateStyle:"full"}));
console.log("Japanese 'full' format         : ",persianToCalendars(1400,12,19,{toCal:"japanese",dateStyle:"full"}));
console.log("Coptic 'full' format           : ",persianToCalendars(1400,12,19,{toCal:"coptic",dateStyle:"full"}));
console.log("Ethioaa 'full' format          : ",persianToCalendars(1400,12,19,{toCal:"ethioaa",dateStyle:"full"}));
console.log("Ethiopic 'full' format         : ",persianToCalendars(1400,12,19,{toCal:"ethiopic",dateStyle:"full"}));
console.log("-".repeat(55));
console.log("Format the input Persian Date without conversion:");
console.log("-".repeat(55));
console.log("Persian 'full' format        : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full"}));
console.log("Persian 'medium' format      : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"medium"}));
console.log("Persian 'short' format       : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"short"}));
console.log("Persian 'ar' locale          : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"ar"}));
console.log("Persian 'fa' locale          : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"fa"}));
console.log("Persian 'hi' locale          : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"hi"}));
console.log("Persian 'ur' locale          : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"ur"}));
console.log("Persian 'ps-AF' locale       : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"ps-AF"}));
console.log("Persian 'id' locale          : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"id"}));
console.log("Persian 'pa' locale          : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"pa"}));
console.log("Persian 'ma' locale          : ",persianToCalendars(1400,12,19,{toCal:"persian",dateStyle:"full", locale:"ma"}));

console.log("-".repeat(55));
console.log("Convert Max Negative and Max Positive Persian Dates to Gregorian");
console.log("-".repeat(55));
console.log(persianToCalendars(-272442,12,29)); // max negative Persian date
console.log(persianToCalendars(275139,6,23));   // max positive Persian date

console.log("-".repeat(55));