format_duration.js

function formatDuration(dur) {
  const timeRange = [60, 60, 24, 1000];
  const units = ['秒', '分钟', '小时', '天'];
  let i = 0;
  let total = dur;

  function getUnitStr(pad) {
    const larger = (total / timeRange[i]) >= 1;
    const base = total % timeRange[i];
    if (base === 0) return '';
    const num = pad && larger ? `0${base}`.slice(-2) : base;
    return `${num} ${units[i]}`;
  }

  // 秒需要补0
  let str = getUnitStr(true);
  while (total >= timeRange[i]) {
    total = Math.floor(total / timeRange[i]);
    i++;
    str = `${getUnitStr()} ${str}`;
  }

  return str;
}