@single-dog-no1/calendar/src/modules/gan_zhi.ts

china lunar calendar

import { getDateString } from './utils';
import { getTimestampBySolar } from './solar';
import { getTermDate } from './term';

// 天干
const ganMap = ['甲', '乙', '丙', '丁', '戊', '己', '庚', '辛', '壬', '癸'];
// 地支
const zhiMap = ['子', '丑', '寅', '卯', '辰', '巳', '午', '未', '申', '酉', '戌', '亥'];

// 获取干支年: 1984年为甲子年
export function getGanZhiYear(lYear: number) {
  let gzIndex = lYear - 1984;
  gzIndex = gzIndex % 60 > 0 ? gzIndex % 60 : gzIndex % 60 + 60;
  let gan = gzIndex % 10;
  let zhi = gzIndex % 12;
  return ganMap[gan] + zhiMap[zhi];
}

// 获取干支月
export function getGanZhiMonth(sYear: number, sMonth: number, sDay: number) {
  let gzIndex = 0;
  let termDate = getTermDate(sYear);
  if (!termDate) {
    throw new Error('year out');
  }
  termDate.push(31);
  termDate.forEach(function (day, index) {
    let month = Math.floor(index / 2) + 1;
    if (getDateString(sMonth, sDay) >= getDateString(month, day)) {
      gzIndex = month;
    }
  });
  gzIndex += (sYear - 1984) * 12;
  gzIndex = gzIndex % 60 > 0 ? gzIndex % 60 : gzIndex % 60 + 60;
  let gan = gzIndex % 10;
  let zhi = gzIndex % 12;
  return ganMap[gan] + zhiMap[zhi];
}

// 获取干支日
export function getGanZhiDay(sYear: number, sMonth: number, sDay: number) {
  let offset = Math.round((getTimestampBySolar(sYear, sMonth, sDay) - getTimestampBySolar(1900, 1, 30)) / 86400000);
  let gzIndex = offset + 39;
  gzIndex = gzIndex % 60 > 0 ? gzIndex % 60 : gzIndex % 60 + 60;
  let gan = gzIndex % 10;
  let zhi = gzIndex % 12;
  return ganMap[gan] + zhiMap[zhi];
}