code: function(target, index, val, clone) {
  
              if (isNaN(index) && index != "first" && index != "last") {
                  error(index + 'is not a valid index.');
                  return;
              }
  
              var type = objType(target),
                  length = target.length;
  
              //to limit index
              var idx = index < 0 || index == "first" ? 0 : index > length || index == "last" ? length : index;
  
  
              //if array push
              if (type == 'array') {
                  val = clone ? jsonQ.clone(val) : val;
                  target.splice(idx, 0, val);
              }
  
              //if string concatenate , if number add
              else if (type == 'string') {
                  target = target.substring(0, idx) + val + target.substring(idx, length);
              }
  
  
              return target;
  
          }
docs: to append at specific index of values of array or string