Promotions only current

I want to show only current promotions

<div class="row" style="padding-left:0px; padding-right: 0px; height: 0vh;">

<?php $eventi = $pages->find('promozioni')->children()->filterBy('negozio', $page->url())->map(function($page) {
$page->timestampfield = strtotime($page->dateend());

return $page;
})->sortBy('timestampfield', 'desc')->paginate(2);
?>

<?php foreach($eventi as $evento):


?><span></span><?php endforeach; ?>





<div class="row" style="padding-top:70px;">

  <div class="col-md-1 pl-0 my-auto">
    <?php


    $pagination = $eventi->pagination();

    ?>


    <?php if($pagination->hasPrevPage()): ?>
    <a class="next" href="<?= $pagination->prevPageURL() ?>"><img src="<?php echo $site->url();?>/assets/images/sinistra.svg"  class="img-fluid" width="100%"></a>
  <?php else: echo ''; ?><?php endif ?>
  </div>
<?php if ($eventi->count() >= 1):?>
<?php foreach($eventi as $evento):
?>

<div class="col-md-5">


  <a href="<?php echo $evento->url();?>" >

	<div class="container">
  <img src="
  <?php if ($evento->hasImages()):
echo thumb($evento->image(), array('width' => 600, 'height' => 600, 'crop' => true))->url();
else:
  $myimage = new Asset('assets/images/granshoppingdefault.jpg');
echo thumb($myimage, array('width' => 600, 'height' => 600, 'crop' => true))->url(); endif;
  ?>

  " class="img-fluid image2" width="100%" style="-webkit-box-shadow: 0px 0px 53px 13px rgba(0,0,0,0.60);
-moz-box-shadow: 0px 0px 53px 13px rgba(0,0,0,0.60);
box-shadow: 0px 0px 53px 13px rgba(0,0,0,0.60);">
  <div class="overlay2">
    <div class="text2"><?php echo $evento->title();?></div>
  </div>
</div>
  </a>
</div>

<?php endforeach; ?><?php else: ?>

<!--<div class="col-md-12 my-auto" style="text-align:center; color: white; font-family: 'Roboto'"><h1>A presto per le nuove promozioni!</h1>  </div>--><?php endif; ?>
  <div class="col-md-1 pl-0 my-auto" >
    <?php if($eventi->pagination()->hasNextPage()): ?>
    <a class="next" href="<?= $eventi->pagination()->nextPageURL() ?>"><img src="<?php echo $site->url();?>/assets/images/destra.svg"  class="img-fluid" width="100%"></a>
   <?php else: echo ''; ?><?php endif ?></div>
</div>

Please choose a question category for your Kirby version, either Kirby 2 question or Kirby 3 question.

it is kirby 2

http://k2.getkirby.com/docs/cookbook/filtering#fun-with-filtering-by-date

I your case, you can filter by timestampfield after the mapping.

so I have to change this code? how?
$page->timestampfield = strtotime($page->dateend());

<?php 
$eventi = $pages->find('promozioni')->children()->filterBy('negozio', $page->url())->map(function($page) {
$page->timestampfield = strtotime($page->dateend());
return $page;
})->filterBy('timestampfield', '>=', time())->sortBy('timestampfield', 'desc')->paginate(2);