Create (TJSon)

constructor Create(const iJsonString:string);

//Procedure JsonParser;
var json:TJson; S,stag:string; idx:Integer;
begin
  json := TJson.Create(
   '{
    "employees": [
    { "firstName":"John" , "lastName":"Doe" },
    { "firstName":"Anna" , "lastName":"Smith" },
    { "firstName":"Peter" , "lastName":"Jones" }
    ]
    }'
  );
 
  S := '';
  for idx:=0 to json.employees.count-1 do
   begin
     S := S+stag+json.employees[idx].firstName;
     stag := ',';
   end;
  showMessage(S);
end;