const peselValidation = (pesel: number) => {
  const peselString = pesel.toFixed()
  const weights = [9, 7, 3, 1, 9, 7, 3, 1, 9, 7];
  let sum = 0;

  for (let index = 0; index < weights.length; index++) {
    sum += parseInt(peselString.substring(index, index + 1), 10) * weights[index];
  }

  sum = sum % 10;
  const response = (sum === parseInt(peselString.substring(10, 11), 10));

  return response;
}

const peselDate = (pesel: number) => {
  const peselString = pesel.toFixed()
  let year: number = parseInt(peselString.substring(0, 2)),
    month: number | string = parseInt(peselString.substring(2, 4), 10) - 1,
    day: number = parseInt(peselString.substring(4, 6), 10)

  const monthString = [
    'stycznia',
    'lutego',
    'marca',
    'kwietnia',
    'maja',
    'czerwca',
    'lipca',
    'sierpnia',
    'września',
    'października',
    'listopada',
    'grudnia'
  ];

  if (year > 80) {
    year = year + 1800
    month = month - 80
  } else if (month > 60) {
    year = year + 2200
    month = month - 60
  } else if (month > 40) {
    year = year + 2100
    month = month - 40
  } else if (month > 20) {
    year = year + 2200
    month = month - 80
  } else {
    year = year + 1900
  }

  return `${day} ${monthString[month - 1]} ${year}`;
}

console.log(peselValidation(73072255843));
console.log(peselDate(73072255843));