[javascript] JavaScript - Get minutes between two dates

Here's some fun I had solving something similar in node.

function formatTimeDiff(date1, date2) {
  return Array(3)
    .fill([3600, date1.getTime() - date2.getTime()])
    .map((v, i, a) => {
      a[i+1] = [a[i][0]/60, ((v[1] / (v[0] * 1000)) % 1) * (v[0] * 1000)];
      return `0${Math.floor(v[1] / (v[0] * 1000))}`.slice(-2);
    }).join(':');
}

const millis = 1000;
const utcEnd = new Date(1541424202 * millis);
const utcStart = new Date(1541389579 * millis);
const utcDiff = formatTimeDiff(utcEnd, utcStart);

console.log(`Dates:
  Start   : ${utcStart}
  Stop    : ${utcEnd}
  Elapsed : ${utcDiff}
  `);

/*
Outputs:

Dates:
  Start   : Mon Nov 05 2018 03:46:19 GMT+0000 (UTC)
  Stop    : Mon Nov 05 2018 13:23:22 GMT+0000 (UTC)
  Elapsed : 09:37:02
*/

You can see it in action at https://repl.it/@GioCirque/TimeSpan-Formatting