身分證字號檢查

isTaiwanId.es6

function isTaiwanId(id) {
  const mapping = [10, 11, 12, 13, 14, 15, 16, 17, 34, 18, 19, 20, 21, 22, 35, 23, 24, 25, 26, 27, 28, 29, 32, 30, 31, 33];
  const ID_REGEX = /^[A-Z][12]\d{8}$/i;

  if (!ID_REGEX.test(id)) {
    return false;
  }

  return `${mapping[id.toUpperCase().charCodeAt(0)-65]}${id.slice(1)}`
    .split('')
    .map(Number)
    .reduce((sum, digit, index) => {
      switch(index) {
        case 0:
        case 10:
          return sum + digit;
        default:
          return sum + digit * (10 - index)
      }
    }, 0) % 10 === 0;
}

console.log(isTaiwanId('A123456789'));
console.log(isTaiwanId('A000000009'));