days-wasted.js

let getTotalDaysInYear = () => {
  let year = new Date().getFullYear();
  if (year % 4 === 0) {
    return 366;
  } else {
    return 365;
  }
};

let getCurrentDayOfYear = () => {
  const ONE_DAY = 1000 * 60 * 60 * 24;
  let currentDay = new Date();
  let startOfTheYear = new Date(currentDay.getFullYear(), 0, 0);
  let difference = currentDay - startOfTheYear;
  let differenceInDays = Math.floor(difference / ONE_DAY);
  return differenceInDays;
};

module.exports = (() => {
  return getCurrentDayOfYear() / getTotalDaysInYear() * 100;
})();