code: function pad(number, size) {
          var stringNum = String(number);
  
          while (stringNum.length < (size || 2)) {
              stringNum = '0' + stringNum;
          }
  
          return stringNum;
      }
docs: Zero padding number
  
  @param  {integer} number     Number to format
  @param  {integer} [size=2]   Digits limit
  @return {string}             Formatted num with zero padding