Sitecore computed field logix to index all the fields of current item in one go

computedfieldSitecoreLogic.txt

Algorithm:
1) Get all the fields of current item
2) Store all fields in an array 
3) create a empty string to store all the item data and call as itemdata (typeof string)
4) Iterate through each item and push data into itemdata
5) Remove all the html using regrex from itemdata if any
6) return itemdata

Basic code

function getallfields(Item currentItem){
List<ID> fieldIds = null;
currentItem.Fields.ReadAll();
foreach (Field field in Item.Fields)
{ 
  fieldIds.Add(field.ID);
}
return fieldIds;
}

function getallData(List<ID> fields ,Item item){
  string itemdata = string.Empty;
  foreach(field in fields){
    itemdata += item[field].Value;
  }
  return itemdata;
}

//Use above function in the computed field and get all the data without need to create multiple computed field logics. 
You can extend this also like if you want to index multilist then you can add case to check if fild.type==multilist then
call getalldata recursively.