code: function getLetterTime(timeString) {
    var totalSeconds = 0;
    var timeValues = {
      's': 1,
      'm': 1 * 60,
      'h': 1 * 60 * 60,
      'd': 1 * 60 * 60 * 24,
      'w': 1 * 60 * 60 * 24 * 7,
    };
    var timePairs;
  
    //expand to "1 h 30 m 20 s" and split
    timeString = timeString.replace(/([smhdw])/g, ' $1 ').trim();
    timePairs = timeString.split(' ');
  
    for (var i = 0; i < timePairs.length; i += 2) {
      totalSeconds += parseInt(timePairs[i], 10) *
        timeValues[timePairs[i + 1] || 's'];
    }
    return totalSeconds;
  }
docs: parses strings like 1h30m20s to seconds