Created
September 16, 2018 18:05
-
-
Save mitsu-ksgr/fe0920464f8d4d82406ffcc6b00be03f to your computer and use it in GitHub Desktop.
干支を返す
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
/** | |
* 指定した西暦の干支を返す. | |
* | |
* @example | |
* console.log(`2018: ${getEto(2018)}`); //> '2018: 戊,戌' | |
* | |
* @param {number} year - 西暦 | |
* @return {Array<string>} [0] 十干, [1] 十二支 | |
*/ | |
const getEto = (year) => { | |
if (!Number.isInteger(year)) throw new Error(`getEto Error: a year must be Number. year = ${year}`); | |
if (year < 0) throw new Error(`getEto Error: a year must be greater than 0. year = ${year}`); | |
const i10 = ["庚", "辛", "壬", "癸", "甲", "乙", "丙", "丁", "戊", "己"]; | |
const i12 = ["子", "丑", "寅", "卯", "辰", "巳", "午", "未", "申", "酉", "戌", "亥"]; | |
// 十二支: 604年から開始らしいので、offsetを考慮する。 offset = -604 % 12 = +8 | |
return [i10[year % 10], i12[(year + 8) % 12]]; | |
}; |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment