text: // https://stackoverflow.com/a/478992/4099022
  function getFirstWeekdayInYear(year){
      const y = year - 1;
      return (year * 365 +
          Math.floor(y / 4) - Math.floor(y / 100) + Math.floor(y / 400)
      ) % 7;
  }
  
  module.exports = getFirstWeekdayInYear;
  