Normally after ajax call we will use Success and Errors as mention below without columns.

success: function(data) {           
        if("success" === data.status){
                        d = transform(data);
            searchResults.clear();
                        searchResults.rows.add(data).draw();
            
        }
        if("error" === data.status){
            deleteCreditCards();
        }
        },
       error : function(data){
         
       } 

But now I am using columns With columns suppose from backend I got error how to display them using coumns.I should have the columns and I need to check the status which we got from backend.

 "ajax": {
    "url": extract_url('/refund/list'),
    "data": function ( d ) {
        var sortingColumn=d.order[0].column;
        var sortingOrder=d.order[0].dir;
        
        d.orderColumn=sortingColumn,
        d.order=sortingOrder;
        d.search = search,
        d.fromDate = fromDate,
        d.toDate = toDate,
        delete d.columns;
    }
  },
    columns: [
      
         {title: "Activity Id", data: "id",
           "render":function(data,type,row,meta){
             data = data !=null ? data:notAvailable;
             return data;            
         }},
         {title: "Date", data: "dateTime",
           "render":function(data,type,row,meta){
             data = moment(data).tz(tenantTimeZone).format(displayFormat);
             return data;            
         }}]

Edited by Kevin: Syntax highlighting. Details on how to highlight code using markdown can be found in this guide