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/*
* Copyright 2020 Adobe. All rights reserved.
* This file is licensed to you under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License. You may obtain a copy
* of the License at http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software distributed under
* the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR REPRESENTATIONS
* OF ANY KIND, either express or implied. See the License for the specific language
* governing permissions and limitations under the License.
*/
// Portions of the code in this file are based on code from ICU.
// Original licensing can be found in the NOTICE file in the root directory of this source tree.
import {AnyCalendarDate, CalendarIdentifier} from '../types';
import {CalendarDate} from '../CalendarDate';
import {fromExtendedYear, getExtendedYear, GregorianCalendar} from './GregorianCalendar';
import {Mutable} from '../utils';
const TAIWAN_ERA_START = 1911;
function gregorianYear(date: AnyCalendarDate) {
return date.era === 'minguo'
? date.year + TAIWAN_ERA_START
: 1 - date.year + TAIWAN_ERA_START;
}
function gregorianToTaiwan(year: number): [string, number] {
let y = year - TAIWAN_ERA_START;
if (y > 0) {
return ['minguo', y];
} else {
return ['before_minguo', 1 - y];
}
}
/**
* The Taiwanese calendar is the same as the Gregorian calendar, but years
* are numbered starting from 1912 (Gregorian). Two eras are supported:
* 'before_minguo' and 'minguo'.
*/
export class TaiwanCalendar extends GregorianCalendar {
identifier: CalendarIdentifier = 'roc'; // Republic of China
fromJulianDay(jd: number): CalendarDate {
let date = super.fromJulianDay(jd);
let extendedYear = getExtendedYear(date.era, date.year);
let [era, year] = gregorianToTaiwan(extendedYear);
return new CalendarDate(this, era, year, date.month, date.day);
}
toJulianDay(date: AnyCalendarDate): number {
return super.toJulianDay(toGregorian(date));
}
getEras(): string[] {
return ['before_minguo', 'minguo'];
}
balanceDate(date: Mutable<AnyCalendarDate>): void {
let [era, year] = gregorianToTaiwan(gregorianYear(date));
date.era = era;
date.year = year;
}
isInverseEra(date: AnyCalendarDate): boolean {
return date.era === 'before_minguo';
}
getDaysInMonth(date: AnyCalendarDate): number {
return super.getDaysInMonth(toGregorian(date));
}
getYearsInEra(date: AnyCalendarDate): number {
return date.era === 'before_minguo' ? 9999 : 9999 - TAIWAN_ERA_START;
}
}
function toGregorian(date: AnyCalendarDate) {
let [era, year] = fromExtendedYear(gregorianYear(date));
return new CalendarDate(
era,
year,
date.month,
date.day
);
}
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