Truncate html

truncate_html.php

<?php

function htmlTruncate(string $html, int $max_lenght) {
    $dom= new \DOMDocument();
    $dom->loadHTML(mb_convert_encoding($html, 'HTML-ENTITIES', 'UTF-8'));

    $xpath = new \DOMXPath($dom);
    $body = $xpath->query('/html/body')->item(0);

    $prev_lenght = 0;
    $removed_children = [];
    foreach ($body->childNodes as  $child_node) {
      if ($prev_lenght > $max_lenght) {
        $removed_children[] = $child_node;
      }
      else {
        $child_lenght = mb_strlen($child_node->textContent);
        $current_lenght = $prev_lenght + $child_lenght;
        if ($current_lenght > $max_lenght) {
          $child_node->nodeValue = mb_substr($child_node->nodeValue, 0, $max_lenght - $prev_lenght);
        }
        $prev_lenght = $current_lenght;
      }
    }
    foreach ($removed_children as $removed_child) {
      $body->removeChild($removed_child);
    }

    return $dom->saveHTML($body);
  }