DST impact on days duration

by Arnaud Buchholz

JavaScript

let from = new Date(2021,0,1,0,0,0,0).getTime()
const dates = {}
for (let days = 0; days < 366; ++days) {
  for (let hours = 0; hours < 24; ++hours) {
    const now = new Date(from + (days * 24 + hours) * 60 * 60 * 1000)
    const dateString = now.toDateString();
    dates[dateString] = (dates[dateString] ?? 0) + 1
  }
}
Object.keys(dates).forEach(dateString => {
  const hours = dates[dateString]
  if (hours !== 24) {
    console.log(dateString, hours)
  }
})