驗證與產生可用的身分證字號

pid.js

// wiki 身分證驗證規則  https://zh.wikipedia.org/wiki/%E4%B8%AD%E8%8F%AF%E6%B0%91%E5%9C%8B%E5%9C%8B%E6%B0%91%E8%BA%AB%E5%88%86%E8%AD%89#%E7%B7%A8%E8%99%9F%E8%A6%8F%E5%89%87

// 中華民國身分證字號英文字首的編號規則數字
const firstLetterMapping = new Map([
  ['A', '10'],
  ['B', '11'],
  ['C', '12'],
  ['D', '13'],
  ['E', '14'],
  ['F', '15'],
  ['G', '16'],
  ['H', '17'],
  ['I', '34'],
  ['J', '18'],
  ['K', '19'],
  ['M', '21'],
  ['N', '22'],
  ['O', '35'],
  ['P', '23'],
  ['Q', '24'],
  ['T', '27'],
  ['U', '28'],
  ['V', '29'],
  ['W', '32'],
  ['X', '30'],
  ['Z', '33'],
  ['L', '20'],
  ['R', '25'],
  ['S', '26'],
  ['Y', '31']
]);

// 驗證規則需要相乘的數
const authMultiplier = [1, 9, 8, 7, 6, 5, 4, 3, 2, 1, 1];

const checkPid = pid => {

  // 長度要為10
  if (pid.length !== 10) return {result: false, msg: '身分證字號長度不正確'};

  // 開頭第一個為英文字母, 後為9個阿拉伯數字, 第一個數字拿來區分性別，男性為1、女性為2
  const re = /^[A-Za-z][12]\d{8}/;
  if (!re.test(pid)) return {result: false, msg: '身分證格式錯誤'};

  // 驗證規則
  const [first, ...nums] = [...pid];
  const source = [...firstLetterMapping.get(first.toUpperCase()), ...nums]
    .map((value, i) => value * authMultiplier[i])
    .reduce((a, b) => a + b, 0);
  
  if (source % 10 !== 0) return {result: false, msg: '驗證失敗'};

  return {result: true};
};


const keys = [...firstLetterMapping.keys()];
const genders = [1, 2];
const nums = [...Array(10).keys()];
const times = [...Array(8).keys()];  // for count 

const genRestNums = () => {
  let restNum = [];
  times.forEach(v => {
    restNum.push(nums[Math.floor(Math.random() * nums.length)]); 
  });

  return restNum.reduce((a, b) => a.toString() + b.toString(), '');
};

// 產生可用的身分證字號
const genPid = () => {
  // gen first letter
  const key = keys[Math.floor(Math.random() * keys.length)];

  // gen second number   1 or 2 
  const firstNum = genders[Math.floor(Math.random() * genders.length)];

  const id = `${key}${firstNum}${genRestNums()}`;

  const {result} = checkPid(id);
  return result ? id : genPid();  
};