Untitled

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width">
  <title>Datas</title>
</head>
<body>
  <table>
    <thead>
      <tr>
        <th>Names</th>
        <th>Ages</th>
      </tr>
    </thead>
    <tbody>
    <tr class="person">
        <td class="name">Breno</td>
        <td class="ages">19</td>
      </tr>
    <tr class="person">
        <td class="name">Maya</td>
        <td class="ages">15</td>
      </tr>
    <tr class="person">
        <td class="name">Fernanda</td>
        <td class="ages">22</td>
      </tr>
    </tbody>
    <tfoot>
      <td>Total Ages</td>
      <td colspan="2" class="total"> ???</td>
    </tfoot>
  </table>
  <script>
  <!-- JAVASCRIPT -->
  const $ = document.querySelectorAll.bind(document);
  $('.total')[0].textContent =
  [...$('.ages')]
    .map(td => parseInt(td.textContent))
    .filter(ages => ages >= 18)
    .reduce((total, ages) => total + ages, 0);

  </script>
</body>
</html>