Drupal 8 - Export content as JSON

Export JSON PHP

$query = \Drupal::entityQuery('node');

$node_ids = $query
    ->condition('status', 1)
    ->exists('field_sidebar')
    ->execute();

$all_nodes_JSON = [];

foreach($node_ids as $node_id) {  
  $node = \Drupal\node\Entity\Node::load($node_id); 
  $sidebar_paragraphs = $node->get('field_sidebar')->referencedEntities();
  foreach($sidebar_paragraphs as $parag) {
      if($parag->getParagraphType()->id == 'related_links') {          
          $related_links = $parag->get('field_related_links')->referencedEntities();
          $related_nids = [];
          foreach($related_links as $linked_entity) {
            $related_node_JSON = [ 
              'id' =>  $linked_entity->id(),
              'url' => 'https://www.mysite.com/node/'.$linked_entity->id()
            ];
            array_push($related_nids, $related_node_JSON);
          }
          $this_node_JSON = [
            'nid' => $node_id,
            'title' => $node->getTitle(),
            'type' => $node->getType(),
            'url' => 'https://www.mysite.com/node/'.$node_id,
            'related_links' => $related_nids
          ];
          array_push($all_nodes_JSON, $this_node_JSON); 
          break;
      }
  }
}
$final_JSON = json_encode($all_nodes_JSON);
print_r($final_JSON);