Create unique IDs and timestamps for new Google Sheet entries

NewEntry.cs

function onEdit(event)
{
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var actSht = event.source.getActiveSheet();
  var actRng = event.source.getActiveRange();
  
  var curRowIndex = actRng.getRowIndex();
  var date = Utilities.formatDate(new Date(), "GMT-4", "MM/dd/yyyy HH:mm:ss");

  // Find column names
  var columnNames = actSht.getRange("1:1").getValues();
  
  for (var i = 0; i < columnNames[0].length; i++)
  {
    var cell = actSht.getRange(curRowIndex, i+1);
    
    if (columnNames[0][i] == "Created At" && cell.getValue() == "" && curRowIndex != 1) 
    {
      cell.setValue(date);
    }
    else if (columnNames[0][i] == "Updated At" && curRowIndex != 1)
    {
      cell.setValue(date);
    }
    else if (columnNames[0][i] == "id" && curRowIndex != 1) 
    {
      if (cell.getValue() == "")
      {
        var headerCell = actSht.getRange(1, i+1);
        var lastId = parseInt(headerCell.getNote());
        ss.toast(lastId + 1);
        
        headerCell.setNote(lastId + 1);
        cell.setValue(lastId + 1);
      }
    }
  }
}