Update Google Sheet column based on other cells in same row.

updateDate.js

function onEdit(e) {
  var range = e.range;
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  var target = "Data";
  var sheet = ss.getSheetByName(target);
  var datestamp = Utilities.formatDate(new Date(), "PST", "dd/MM/yyyy hh:mm:ss a");

  
  // SpreadsheetApp.getUi().alert("Edited in A1 Notation is: " + range.getA1Notation() + "\nDatestamp: " + datestamp ); //If you're having problems, uncomment this to make sure your named range is properly defined  
  
  if (sheet.getName() == target) {
    var row = range.getRow();
    var col = range.getColumn();
    var headers = sheet.getRange(1, 1, 1, sheet.getLastColumn()).getValues();
    
    if ( row >1 ){
    var timestampCol =  headers[0].indexOf("Last updated")+1;
    var completeCol =  headers[0].indexOf("Completed")+1;    
    
    // DateStamp
    sheet.getRange(row, timestampCol).setValue(datestamp);
    // Sets the first column to a width which fits the text
    sheet.autoResizeColumn(timestampCol);
    
    // Put a comment to show the last edit date and name (if we can) as a comment on the cell
      var userName = Session.getEffectiveUser().getUsername();
      range.setNote("");
      range.setNote("modified: " + datestamp+"\nby: "+userName);
      myArchive();
    }

//    Check for Overdue ?
//    var overdueCol = headers[0].indexOf("Follow up by"); 

//    var targetHeaders = [
//      "Requestor name",
//      "Recipient \(if different than Requestor\)",
//      "Contact info",
//      "Request date",
//      "Type of request",
//      "Contact with Requester?",
//      "Volunteer Confirmed",
//      "Notes",
//      "Estimated end date",
//      "Follow up by",
//      "Completed"
//    ];
//    
   // figure out which column name was edited
//    var actualHeader = headers[0][col-1];
//    Logger.log("overdueCol: " +overdueCol+1 + "\n   actualheader is: " + actualHeader+"\n   header?"+headers[0]);
// 
//    if (targetHeaders.indexOf(actualHeader) == -1) {
//       Logger.log("IF\n" + actualHeader + "\n col: " + targetHeaders.indexOf(actualHeader) + "\n row: " + row + "\n timestampCol: " + timestampCol);
//      return;
//    } else {
//      Logger.log("ELSE\n" + actualHeader + "\n col: " + actualHeader.indexOf() + "\n row: " + row + "\n timestampCol: " + timestampCol);
//      //sheet.getRange(row, timestampCol).setValue(datestamp);
//    }      
  }
}