humanReadableTimeStringToSeconds.js

/**
 * Returns the time string as Number in seconds.
 * @param {string} str - String with human readable time for example "15m 45s"
 * @returns {number} Seconds as Number
 */
function humanReadableTimeStringToSeconds(str) {
  const units = ['d', 'h', 'm', 's'];
  const regex = RegExp('^(\\d+)(['+units.join('')+'])$', 'i');
  const unitConversions = [86400, 3600, 60, 1];
  const parts = str.split(/\s+/) || [str];
  return parts.reduce((a, c) => {
    const m = c.match(regex);
    if (m === null) {
      return a;
    }
    const val = Number(m[1]);
    const unit = m[2];
    return a + (val * unitConversions[units.indexOf(unit)]);
  }, 0);
}