Google Sheets API v4 - How to get the last row with value?

You can set the range to "A2:D" and this would fetch as far as the last data row in your sheet.

I managed to get it by counting the total rows from current Sheets. Then append the data to the next row.

rowcount = this.mService.spreadsheets().values().get(spreadsheetId, range).execute().getValues().size()