I have been trying to create an Apps Script that records new answers to a Google Form in Google Sheet.

The reason why I need it is:

1. I need users to be able to file max 1 answer per month, but then re-use the same form each month. I.e. Users can't file more the one answer within the same month but they can file one answers per month.
2. I need a record of all answers for every month in a single Tab of Google Sheet and want to minimize manual work.

Hence, my procedure is deleting all answers from the Form and re-sending the same link to the filer group. I have used the below script which records all answers correctly. Problem is that if an answer is left unchanged with respect to the previous month from the same user, the corresponding cell is blank.

function copyLastRow(event) {  
  var target = SpreadsheetApp.openById('spreadsheetID').getSheetByName('all responses');
  target.appendRow(event.values);
}

This is how the responses look like with the script above. All of those answers have been submitted by the same google account, and when a response is left unchanged, it records a blank cell.

I would be looking to get still the text of the answer even if it has been left unchanged with respect to the previous month.

See how it records in Google Sheets