Перевірка ІПН

checkIPN.js

const mult = [-1, 5, 7, 9, 4, 6, 10, 5, 7]
const sourceDate = new Date('1899-12-31')

const checkIPN = str => {
  const daysSinceBirthday = parseInt(str.slice(0, 5))
  let birthday = new Date(sourceDate).setDate(sourceDate.getDate() + daysSinceBirthday + 1)
  birthday = new Date(birthday)
  const sex = parseInt(str.slice(8,9)) % 2 === 0 ? 'Жінка' : 'Чоловік'
  const numbers = str.slice(0,9).split('').map(el => parseInt(el))
  const checkSum = numbers.reduce((acc, val, i) => acc + val * mult[i], 0) % 11 % 10
  const result = parseInt(str.slice(9, 10)) === checkSum
  return { birthday, sex, result }
}