Convert seconds to days, hours, minutes and seconds

Question

I have a Javascript timing event with an infinite loop with a stop button.

It will display numbers when start button is click.Now I want this numbers converted to so

Answer 1

My solution with map() and reduce():

const intervalToLevels = (interval, levels) => {
  const cbFun = (d, c) => {
    let bb = d[1] % c[0],
      aa = (d[1] - bb) / c[0];
    aa = aa > 0 ? aa + c[1] : '';

    return [d[0] + aa, bb];
  };

  let rslt = levels.scale.map((d, i, a) => a.slice(i).reduce((d, c) => d * c))
    .map((d, i) => ([d, levels.units[i]]))
    .reduce(cbFun, ['', interval]);
  return rslt[0];
};

const TimeLevels = {
  scale: [24, 60, 60, 1],
  units: ['d ', 'h ', 'm ', 's ']
};
const secondsToString = interval => intervalToLevels(interval, TimeLevels);

If you call secondsToString(123456), you can get "1d 10h 17m 36s "