How to stop a TimeStamp from changing on every edits using Apps Script?

Question

I require some guidance regarding Google Apps Script, as I am a novice and facing some challenges while constructing a script. Presently, I have produced a script that registers the timestamp whenever there is an alteration in specific columns across two distinct tabs. However, I am encountering an issue where the timestamp changes every time there is an edit in those cells. My objective is to create a script that captures the timestamp only on the initial edit and does not alter it subsequently. Below, you can find my current script. I would greatly appreciate any assistance that can be extended.

function onEdit() {
  var s = SpreadsheetApp.getActiveSheet();
  if( s.getName() == "Production Activity" ) { //checks that we're on the correct sheet
    var r = s.getActiveCell();
    if( r.getColumn() == 25 ) { //checks the column
      var nextCell = r.offset(0, 1);
      //if( nextCell.getValue() !== '' ) //is empty?
      nextCell.setValue(new Date());
    }

    if( r.getColumn() == 27 ) { //checks the column
      var nextCell = r.offset(0, 1);
      //if( nextCell.getValue() !== '' ) //is empty?
      nextCell.setValue(new Date());
    }
  }
  if( s.getName() == "Non-Production Activity" ) { //checks that we're on the correct sheet
    var r = s.getActiveCell();
    if( r.getColumn() == 9 ) { //checks the column
      var nextCell = r.offset(0, 1);
      //if( nextCell.getValue() !== '' ) //is empty?
      nextCell.setValue(new Date());
    }

    if( r.getColumn() == 11 ) { //checks the column
      var nextCell = r.offset(0, 1);
      //if( nextCell.getValue() !== '' ) //is empty?
      nextCell.setValue(new Date());
    }
  }
}

Answer 1

In your situation and script, how about using isBlank() method of Class Range? When this is reflected in your script, how about the following modification?

Modified script:

function onEdit() {
  var s = SpreadsheetApp.getActiveSheet();
  if (s.getName() == "Production Activity") { //checks that we're on the correct sheet
    var r = s.getActiveCell();
    if (r.getColumn() == 25) { //checks the column
      var nextCell = r.offset(0, 1);
      if (nextCell.isBlank()) {
        nextCell.setValue(new Date());
      }
    }

    if (r.getColumn() == 27) { //checks the column
      var nextCell = r.offset(0, 1);
      if (nextCell.isBlank()) {
        nextCell.setValue(new Date());
      }
    }
  }
  if (s.getName() == "Non-Production Activity") { //checks that we're on the correct sheet
    var r = s.getActiveCell();
    if (r.getColumn() == 9) { //checks the column
      var nextCell = r.offset(0, 1);
      if (nextCell.isBlank()) {
        nextCell.setValue(new Date());
      }
    }

    if (r.getColumn() == 11) { //checks the column
      var nextCell = r.offset(0, 1);
      if (nextCell.isBlank()) {
        nextCell.setValue(new Date());
      }
    }
  }
}

• When I saw your script and question, when the event object is used, I thought that the script might be simple. When this is reflected in the script, how about the following modified script?

  function onEdit(e) {
    const obj = {
      "Production Activity": [25, 27],
      "Non-Production Activity": [9, 11]
    };
    const { range } = e;
    const o = obj[range.getSheet().getSheetName()];
    if (o && o.includes(range.columnStart)) {
      const dstRange = range.offset(0, 1);
      if (dstRange.isBlank()) {
        dstRange.setValue(new Date());
      }
    }
  }
  

References:

• isBlank()
• Event Objects