export default function parseDate(iso8601: string): Date | null {
  const regexp = new RegExp(
    '^([0-9]{1,4})-([0-9]{1,2})-([0-9]{1,2})' +
      'T' +
      '([0-9]{1,2}):([0-9]{1,2}):([0-9]{1,2})' +
      '(.([0-9]+))?' +
      'Z$'
  );
  const match = regexp.exec(iso8601);
  if (!match) {
    return null;
  }

  const year = parseInt(match[1]) || 0;
  const month = (parseInt(match[2]) || 1) - 1;
  const day = parseInt(match[3]) || 0;
  const hour = parseInt(match[4]) || 0;
  const minute = parseInt(match[5]) || 0;
  const second = parseInt(match[6]) || 0;
  const milli = parseInt(match[8]) || 0;

  return new Date(Date.UTC(year, month, day, hour, minute, second, milli));
}