const learnedSomething = () => Math.random() <= .5;
const alive = (d) => d.getFullYear() <= 2017;
const now = new Date(2017, 7, 1);
const today = new Date(now.getFullYear(), now.getMonth(), now.getDate());
const tomorrow = (d) => new Date(d.getFullYear(), d.getMonth(), d.getDate() + 1);
const life = (function* (today) {
  while (alive(today))
    yield { date: today = tomorrow(today), learnedSomething: learnedSomething() };
})(today);
let stringDate;
let prevStringDate;
for (let day of life) {
  console.log(day.date);
  stringDate = day.date.toLocaleDateString('en', { day: 'numeric', month: 'long', year: 'numeric', weekday: 'long' });
  if (stringDate === prevStringDate) {
     throw new Error('Invalid date calculation');
  }
  console.log(`${stringDate} was ${day.learnedSomething ? 'a decent day' : 'ok'}`);
  prevStringDate = stringDate;
}