const second = 1000;
const minute = second*60;
const hour = minute*60;
const day = hour*24;

const countdown = (target, heading) => {
    const now = new Date();
    const diff = target - now;

    const timeleft = {}; 
    timeleft.days = Math.trunc(diff/day);
    timeleft.hours = Math.trunc(diff%day/hour);
    timeleft.minutes = Math.trunc(diff%day%hour/minute);
    timeleft.seconds = Math.trunc(diff%day%hour%minute/second);

    const formatted = Object.keys(timeleft).map((unit) => {
        // retrieve value, cast it to string and optionally pad it with a leading 0
        return timeleft[unit]
        .toString()
        .padStart(2, '0');
    });

    return `
<h${heading}>${formatted[0]} Days</h${heading}>
<h${heading}>${formatted[1]} Hours</h${heading}>
<h${heading}>${formatted[2]} Minutes</h${heading}>
<h${heading}>${formatted[3]} Seconds</h${heading}>
`;
};

const hash_date = new Date(location.hash.substr(1))
const update_all = () => {
    let i = 1
    const date_list = location.hash.split('#').slice(1).map((fragment) => {return new Date(fragment)})
    document.getElementById('output').innerHTML = countdown(date_list[0], i);
}
update_all();
setInterval(update_all, 500);