Script changing dates to text

Try this for replace dates with text:

1. Inserts helper columns with TEXT() formulas.
2. Converts them to plain text.
3. Copies the values back to the original columns.
4. Deletes the helper columns.

function main(workbook: ExcelScript.Workbook) {
  let sheet = workbook.getActiveWorksheet();
  let table = sheet.getTables()[0]; // Assumes there's only one table on the sheet

  // Add helper columns to the table
  table.addColumn(5, true).getRangeBetweenHeaderAndTotal().setFormulaLocal("=TEXT([@Geboortedatum],\"dd/mm/yyyy\")");
  table.getColumn(5).getRange().setNumberFormatLocal("@");

  table.addColumn(17, true).getRangeBetweenHeaderAndTotal().setFormulaLocal("=TEXT([@[Datum Resultaat]],\"dd/mm/yyyy\")");
  table.getColumn(17).getRange().setNumberFormatLocal("@");

  table.addColumn(19, true).getRangeBetweenHeaderAndTotal().setFormulaLocal("=TEXT([@Startdatum],\"dd/mm/yyyy\")");
  table.getColumn(19).getRange().setNumberFormatLocal("@");

  // Copy values from helper columns back to original columns
  let rowCount = table.getRowCount();
  for (let i = 0; i < rowCount; i++) {
    let geboortedatumText = table.getColumn(5).getDataBodyRange().getCell(i, 0).getText();
    let datumResultaatText = table.getColumn(17).getDataBodyRange().getCell(i, 0).getText();
    let startdatumText = table.getColumn(19).getDataBodyRange().getCell(i, 0).getText();

    table.getColumnByName("Geboortedatum").getDataBodyRange().getCell(i, 0).setValue(geboortedatumText);
    table.getColumnByName("Datum Resultaat").getDataBodyRange().getCell(i, 0).setValue(datumResultaatText);
    table.getColumnByName("Startdatum").getDataBodyRange().getCell(i, 0).setValue(startdatumText);
  }

  // Delete helper columns (assuming they were inserted at fixed positions)
  table.getColumn(19).delete();
  table.getColumn(17).delete();
  table.getColumn(5).delete();
}