App Script to add new text to existing notes in Google Sheets - google-apps-script

Question

Working in AppScript with Google Sheets and I have this script working to add notes based off of a cell value in a different column (selectedCell3 portion of the script). I'm wanting to add logic that essentially ADDS new text to the notes IF the cell value is changed. This is as far as I've gotten...
Still learning... be kind :)
//* Creates a Date Stamp if a column is edited.
//*/
//CORE VARIABLES
// The column you want to check if something is entered.
var COLUMNTOCHECK = 22;
// The SECOND column you want to check if something is entered.
var COLUMNTOCHECK2 = 18;
// The THIRD column you want to check if something is entered.
var COLUMNTOCHECK3 = 10;
// Where you want the date time stamp offset from the input location. [row, column]
var DATETIMELOCATION = [0,1];
// Where you want the SECOND date time stamp offset from the input location. [row, column]
var DATETIMELOCATION2 = [0,1];
// Where you want the THIRD date time stamp offset from the input location. [row, column]
var DATETIMELOCATION3 = [0,1];
// Sheet you are working on
var SHEETNAME = 'PM AUGUST 2022'
function onEdit(e) {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var sheet = ss.getActiveSheet();
// var notesSheet = ss.getSheets()[0];
// var values_range = sheet.getRange("L2:L" + sheet.getLastRow());
// var notes_range = sheet.getRange("Z2:Z" + sheet.getLastRow());
// var notes = notes_range.getValues();
//checks that we're on the correct sheet.
if( sheet.getSheetName() == SHEETNAME ) {
var lastRow = sheet.getLastRow();
var selectedCell = ss.getActiveCell();
//checks the column to ensure it is on the one we want to cause the date to appear.
if( selectedCell.getColumn() == COLUMNTOCHECK && selectedCell.getValue() == "Billing") {
var dateTimeCell = selectedCell.offset(DATETIMELOCATION[0],DATETIMELOCATION[1]);
dateTimeCell.setValue(new Date());
}
var selectedCell2 = ss.getActiveCell();
if (selectedCell2.getColumn()==COLUMNTOCHECK2 && selectedCell2.getValue() !== ""){
var dateTimeCell2 = selectedCell2.offset(DATETIMELOCATION2[0],DATETIMELOCATION2[1]);
dateTimeCell2.setValue(new Date());
}
var selectedCell3 = ss.getActiveCell();
//var notesSheet = ss.getSheets()[0];
var values_range = sheet.getRange("J2:J" + lastRow);
var notes_range = sheet.getRange("L2:L" + lastRow);
var notes = notes_range.getValues();
var oldValue = notes.oldValue;
if (selectedCell3.getColumn()==COLUMNTOCHECK3 && selectedCell3.getValue() !== ""){
var dateTimeCell3 = selectedCell3.offset(DATETIMELOCATION3[0],DATETIMELOCATION3[1]);
dateTimeCell3.setValue(new Date());
if (oldValue != null) {
notes += 'Prior Entry :' + oldvalue;
}
values_range.setNotes(notes);
}
}
}

Answer 1

I think this is what you were shooting for
function onEdit(e) {
var sh = e.range.getSheet();
if (sh.getName() == 'PM AUGUST 2022') {
var lastRow = sh.getLastRow();
if (e.range.columnStart == 22 && e.value == "Billing") {
e.range.offset(0, 1).setValue(new Date());
}
if (e.range.columnStart == 18 && e.value !== "") {
e.range.offset(0, 1).setValue(new Date());
}
if (e.range.columnStart == 10 && e.value !== "") {
e.range.offset(0, 1).setValue(new Date());
let ts = Utilities.formatDate(new Date(), Session.getScriptTimeZone(), "yyyy MM dd HH:mm:ss")
sh.getRange(e.range.rowStart, 10).setNote(sh.getRange(e.range.rowStart, 10).getNote() + '\n' + sh.getRange(e.range.rowStart, 10).getValue() + ts);
}
}
}
Demo: