convert html to editor js readable format

HTML2EditorJS.php

<?php

use DOMDocument;
use DOMNode;
use DOMNodeList;
use Illuminate\Support\Collection;

final class HTML2EditorJS
{
  private $document;
  private $html;
  private $result;

  function __construct($html)
  {
    $this->html = $html;
    $this->document = new DOMDocument();
    if ($this->html) {
      $this->document->loadHTML($this->html);
    }

    $this->result = [
      'time' => time(),
      'version' => "2.15.0",
      'blocks' => []
    ];
  }

  public function toArray()
  {
    if (!$this->html) {
      return $this->result;
    }

    $body = $this->document->getElementsByTagName('body');
    $children = $this->getChildren($body->item(0));
    $blocks = $children
      ->map(function (DOMNode $item) {
        if ($item->nodeName === 'p') {
          return $this->parseParagraph($item);
        }

        if (str_contains($item->nodeName, 'h')) {
          return $this->parseHeader($item);
        }
        if ($item->nodeName === 'ol' || $item->nodeName === 'ul') {
          return $this->parseList($item);
        }
        return null;
      })
      ->filter(function ($item) {
        return $item !== null;
      })
      ->values()
      ->toArray();

    $this->result['blocks'] = $blocks;
    return $this->result;
  }


  /**
   * @param DOMNode $p
   * @return array
   */
  private function parseParagraph($p)
  {
    return [
      'type' => 'paragraph',
      'data' => [
        'text' => $this->saveTextFromNode($this->innerHTML($p))
      ]
    ];
  }

  /**
   * @param DOMNode $header
   * @return array
   */
  private function parseHeader($header)
  {
    return [
      'type' => 'header',
      'data' => [
        'text' => $this->saveTextFromNode($this->innerHTML($header)),
        'level' => str_replace('h', '', $header->nodeName),
      ]
    ];
  }

  /**
   * @param DOMNode $list
   * @return array
   */
  private function parseList($list)
  {
    return [
      'type' => 'list',
      'data' => [
        'style' => $list->nodeName === 'ol' ? 'ordered' : 'unordered',
        'items' => $this->getChildren($list)
          ->map(function (DOMNode $item) {
            return $this->saveTextFromNode($this->innerHTML($item));
          })->toArray()
      ]
    ];
  }

  /**
   * @param string $text
   * @return string
   */
  private function saveTextFromNode($text)
  {
    return trim(utf8_decode($text));
  }

  /**
   * @param DOMNode $node
   * @return Collection<DOMNode>
   */
  private function getChildren($node)
  {
    return $this->DOMListToCollection($node->childNodes);
  }

  /**
   * @param DOMNodeList $domList
   * @return Collection<DOMNode>
   */
  private function DOMListToCollection($domList)
  {
    return collect(iterator_to_array($domList));
  }

  /**
   * @param DOMNode $node
   * @return string
   */
  private function innerHTML($node)
  {
    return implode(
      array_map(
        [$node->ownerDocument, "saveHTML"],
        iterator_to_array($node->childNodes)
      )
    );
  }
}