Google Sheet Macro to Hide Unused rows

 /**

 * Delete the empty rows and columns outside of the DataRange()

 */

function deleteExternalEmptyRowsNColumns() {

  // get sheets and data

  const ss = SpreadsheetApp.getActiveSheet();

  const data = ss.getDataRange().getValues();

  //console.log(data);

  // determine last row and column

  const lastRow = data.length;

  const lastCol = data[0].length;

  // get maximum rows and columns sss

  const maxRows = ss.getMaxRows();

  const maxCols = ss.getMaxColumns();

  // only remove rows and columns if there are empty rows or columns beyond last row and columns

  if (maxRows > lastRow) {

    ss.deleteRows(lastRow + 1, maxRows - lastRow);

  }

  if (maxCols > lastCol) {

    ss.deleteColumns(lastCol + 1, maxCols - lastCol);

  }

}