Set value on form submission based on previous row

Question

I have a script that triggers on form submission, checks the row before last row and should write a TRUE value to the 9th column of the checked row IF all three cells on its left have a TRUE value.

My problem is that the script always writes a FALSE value, even if the 3 cells on the left are all TRUE.

function onFormSubmit() {
var s = SpreadsheetApp.getActiveSpreadsheet(); 
var rcore = s.getSheetByName("test");
var lastrow = rcore.getLastRow();

var trgt = rcore.getRange(lastrow-1,9);

if(trgt.getValue() === ""){
  if(trgt.offset(0, -3) == "TRUE" && trgt.offset(0, -2) == "TRUE" && trgt.offset(0, -1) == "TRUE"){
    trgt.setValue("TRUE");
  } else {
  trgt.setValue("FALSE");
  }
  }
}

(My language is set to hungarian so that's why you see "IGAZ" for "TRUE" values and "HAMIS" for "FALSE" values)

The 3 TRUE/FALSE values are generated by ARRAYFORMULA. Maybe that is also important

---

SO FAR I have tried several variations: -tried to change the if to check with offset (0, -4) if its equal to 2 and not check anything else, but still I got FALSE values. -I also tried to check with different if statements but it always gives FALSE. -tried to check what happens if I also offset row to -1

I simply cant get a TRUE value. The last time I was able to get a TRUE value was when there was no other if statement, only one that checks if the cell is empty or not.

Answer 1

As Rubén pointed out, you need to use .getValue() to read the value in a range. You should also use the Boolean values true and false instead of the text strings "TRUE" and "FALSE", like this:

function onFormSubmit() {
  const ss = SpreadsheetApp.getActive();
  const rcore = ss.getSheetByName('test');
  const lastRow = rcore.getlastRow();
  const trgt = rcore.getRange(lastRow - 1, 9);
  if (trgt.getValue() === '') {
    if (trgt.offset(0, -3).getValue() === true && trgt.offset(0, -2).getValue() === true && trgt.offset(0, -1).getValue() === true) {
      trgt.setValue(true);
    } else {
      trgt.setValue(false);
    }
  }
}

...or more concisely:

function onFormSubmit() {
  const rcore = SpreadsheetApp.getActive().getSheetByName('test');
  const trgt = rcore.getRange(rcore.getlastRow() - 1, 9);
  if (trgt.getValue() === '') {
    trgt.setValue(trgt.offset(0, -3, 1, 3).getValues().flat().every(value => value === true));
  }
}