Clear Data in Server Side Row Model for each API Call in Ag Grid

Question

My requirement is to load complete data for each API call in server side row model. My backend api will ignore startIndex and return all data from 0 to lastIndex. This is done to modify any data which is changed. While trying this, the old data loaded in ag-grid is not deleted. So new data is always appended to old data. I have created plunker project for this:

https://plnkr.co/edit/dMw6oofP3hYPT1JR

getRows: function (params) {      
      var response = server.getData(params.request);
      setTimeout(function () {        
        if (response.success) {
          params.success({
            rowData: response.rows,
            rowCount: response.lastRow,
          });
        } else {
          params.fail();
        }
      }, 1000);

Please help me to delete ag-grid data in server side row model. SO I can load new data on each api call while infinite scroll.