old_contents: function reverseString(str) {
      var reversedString = '';
      for(var i = str.length - 1; i >= 0 ; i--) {
          reversedString += str[i];
      }
      return reversedString;
  }
  
new_contents: function reverseString(text) {
      text = text.split('');
      var len = text.length,
          halfIndex = Math.floor(len / 2) - 1,
          revText;
      for (var i = 0; i <= halfIndex; i++) {
          revText = text[len - i - 1];
          text[len - i - 1] = text[i];
          text[i] = revText;
      }
      return text.join('');
  }
  
  function reverseStringNatively(text) {
      return (!text || text.length < 2) ? text : text.split('').reverse().join('');
  }
  
subject: add methods for string reverse algorithm