如果農曆的日期同時提供一個數字鍵值較好，這樣就無需另作轉換了。謝謝 about chinese-lunar HOT 12 CLOSED

lunar('2020', '03', '28').getJson().lunarPerMonthHasDays;
// return [ '29',  '30',  '30',  '30',  '29',  '30',  '29',  '29',  '30',  '29',  '30',  '29',  '30' ]

const data = lunar().setChineseAge('甲子').getJson();

{
  year: '2020',
  month: '04',
  day: '02',
  solarTerms: '春分',
  lunarMonth: '三月',
  lunarDay: '初十',
  lunarMonthDigit: 3,
  lunarDayDigit: 10,
  isLunarLeapMonth: false,
  leapMonth: 4,
  chineseYear: '庚子',
  chineseMonth: '己卯',
  chineseDay: '乙亥',
  chineseTimes: [
    '丙子', '丁丑', '戊寅',
    '己卯', '庚辰', '辛巳',
    '壬午', '癸未', '甲申',
    '乙酉', '丙戌', '丁亥'
  ],
  week: '4',
  animal: '鼠',
  constellation: '牡羊座',
  chineseFeb: true,
  chineseTimesTenGod: [
    '食', '傷', '才', '財',
    '殺', '官', 'ㄗ', '印',
    '比', '劫', '食', '傷'
  ],
  dengGui: '丑酉',
  lunarPerMonthHasDays: [
    '29', '30', '30',
    '30', '29', '30',
    '29', '29', '30',
    '29', '30', '29',
    '30'
  ],
  chineseTime: '壬午',
  chineseTimeTenGod: 'ㄗ',
  chineseYearTenGod: '殺',
  chineseMonthTenGod: '財',
  chineseDayTenGod: '劫',
  solarTermDistance: {
    previous: {
      solarTerm: '驚蟄',
      diffDistanceDay: 28,
      diffDistanceDetail: 27.543935185185187
    },
    next: {
      solarTerm: '清明',
      diffDistanceDay: 2,
      diffDistanceDetail: 2.651412037037037
    }
  },
  nayin: '土',
  purpleWhites: [
    '八白', '七赤', '六白',
    '五黃', '四綠', '三碧',
    '二黑', '一白', '九紫',
    '八白', '七赤', '六白'
  ]
}