Script error - TypeError: Cannot read properties of undefined

Question

My current script will unlock a range of cells C8:D60. If this range is already unlocked, the script will cause an error message - TypeError: Cannot read properties of undefined (reading 'remove')

How do I test if range is unlocked first and prevent the error message? Thanks in advance!

function UnlockFriday() {
  var spreadsheet = SpreadsheetApp.openById('al;dskfjlasdjfl;asdfl;jkasf');
  spreadsheet.getRange('C8:D60').activate();
  var allProtections =     spreadsheet.getActiveSheet().getProtections(SpreadsheetApp.ProtectionType.RANGE);
  var matchingProtections = allProtections.filter(function(existingProtection) {
  return existingProtection.getRange().getA1Notation() == 'C8:D60';
  });
  var protection = matchingProtections[0];
  protection.remove();
};

Answer 1

In the case of your showing script, how about the following modification?

Modified script:

function UnlockFriday() {
  var spreadsheet = SpreadsheetApp.openById('al;dskfjlasdjfl;asdfl;jkasf');
  spreadsheet.getRange('C8:D60').activate();
  var allProtections = spreadsheet.getActiveSheet().getProtections(SpreadsheetApp.ProtectionType.RANGE);
  var matchingProtections = allProtections.filter(function (existingProtection) {
    return existingProtection.getRange().getA1Notation() == 'C8:D60';
  });

  if (matchingProtections.length == 0) return; // Added

  var protection = matchingProtections[0];
  protection.remove();
}

• By this modification, when the length of matchingProtections is 0, the script is finished. By this, your error can be avoided.

• As another approach, when find is used instead of filter, it becomes as follows.

  function UnlockFriday() {
    var spreadsheet = SpreadsheetApp.openById('al;dskfjlasdjfl;asdfl;jkasf');
    spreadsheet.getRange('C8:D60').activate();
    var allProtections = spreadsheet.getActiveSheet().getProtections(SpreadsheetApp.ProtectionType.RANGE);
    var matchingProtection = allProtections.find(existingProtection => existingProtection.getRange().getA1Notation() == 'C8:D60');
    if (!matchingProtection) return;
    matchingProtection.remove();
  }