Google Sheets: Script to fix ROUNDUP() to be compatible with Excel export

fixRoundupFunctionForExcelExport.gs

// Excel needs ROUNDUP() to always have a second argument while in Google Sheets it defaults to 0.
// This script adds the missing ";0" to any use of ROUNDUP() in the current spreadsheet.
function fixRoundupForExcel() {
  var ss = SpreadsheetApp.getActiveSpreadsheet();
  
  // Go thru each sheet
  var sheets = ss.getSheets();
  for (var s = 0; s < sheets.length; s++) {
    var sheet = sheets[s];
    var range = sheet.getDataRange();
    
    // Go thru each cell formula
    var formulas = range.getFormulas();
    for (var r = 0; r < formulas.length; r++) {
      for (var c = 0; c < formulas[r].length; c++) {
        var formula = formulas[r][c];
        if(formula) {
          var fixed = false;
          // Iterate over all occurrences of "ROUNDUP("
          var offset = -1;
          while ((offset = formula.toLowerCase().indexOf('roundup(', offset + 1)) != -1) {
            // Parse possibly nested formula
            var openBrackets = 0, inString = false;
            formulaParsing:
            for (var pos = offset, l = formula.length; pos < l; pos++) {
              var char = formula.substr(pos, 1);
              switch (char) {
                case "'":
                case '"':
                  // Keep track of whether we're in a string
                  inString = !inString;
                  break;
                case '(':
                  // Keep track of open brackets
                  if (!inString) {
                    openBrackets++;
                  }
                  break;
                case ')':
                  if (!inString) {
                    openBrackets--;
                  }
                  
                  if(openBrackets == 0) {
                    // Separate complete ROUNDUP(...) function
                    var func = formula.substr(offset, pos - offset + 1);
                    
                    // If there is no decimals argument
                    if (!func.match(/;\s*[0-9]+\s*\)$/)) {
                      // Insert ";0" decimals argument
                      formula = formula.substr(0, offset) + formula.substr(offset, pos - offset) + ';0' + formula.substr(pos);
                      fixed = true;
                    }
                    
                    break formulaParsing;
                  }
              }
            }
          }
          if(fixed) {
            sheet.getRange(r + 1, c + 1).setFormula(formula);
            
            Logger.log(sheet.getName() + ': R' + (r + 1) + 'C' + (c + 1) + ': ' + formula);
          }
        }
      }
    }
  }
}