use entityQuery within a Block plugin

Question

I'm attempting to use queries within a block plugin to avoid using views for performance purposes.

namespace Drupal\my_plugins\Plugin\Block;

use Drupal\Core\Block\BlockBase;
use Drupal\Core\Form\FormStateInterface;
use Drupal\Core\Entity\Query;

/**
 * @Block(
 *   id = "basic_text",
 *   admin_label = @Translation("Basic Block")
 * )
 */

class Basic extends BlockBase {

    /**
     * {@inheritdoc}
     */
    public function defaultConfiguration() {
        return array(
            'bodytext-submit' => $this->t('Enter text here'), 
            'layout' => array('pane-type-submit' => 'box'),
            );
    }

    /**
     * {@inheritdoc}
     */
    public function blockForm($form, FormStateInterface $form_state){
        include 'StyleForm.php';

        $form['bodytext'] = array(
          '#type' => 'text_format',
          '#title' => $this->t('Block contents'),
          '#format' => 'full_html',
          '#description' => $this->t('This text will appear in the block.'),
          '#default_value' => $this->configuration['bodytext-submit'],
        );
        return $form;
    }

    public function blockSubmit($form, FormStateInterface $form_state) {
        $this->configuration['bodytext-submit']  = $form_state->getValue('bodytext');
        }

    public function build(){
        $query = \Drupal::entityQuery('node');
        $nids = $query->execute();
        return array(
            '#type' => 'markup',
            '#markup' => $this->configuration['bodytext-submit']['value'],
        );
    }
}

I ultimately want to be able to perform a query and display a list of nodes that fulfill a certain requirement. As a test I performed an empty query for all nodes without displaying any of the results. But when I add

$query = \Drupal::entityQuery('node');
$nids = $query->execute();

to the build() function. It makes it so I can't render the block. I would like to be able to perform entity queries and display the results within the block.

Answer 1

Sorry Maouna, but don't you need to load the nodes and not just find the nids ? Something like :

$build = [
   '#theme' => 'item_list',
   '#items' => array(),
  ];

    $entity_type = 'node';
    $storage = \Drupal::entityTypeManager()->getStorage($entity_type); 
    $nodes = $storage->loadMultiple($nids);
    $view_builder = \Drupal::entityTypeManager()->getViewBuilder($entity_type);
    $view_mode = 'teaser'; // You can change for another view_mode if that suits you. You can considere creating one.

    foreach ($nodes as $node) {
      $build['#items'][] = $view_builder->view($node, $view_mode);
    }

return $build;

Answer 2

There are brackets missing:

$nids = $query->execute();

In my block this works:

 public function build() {
   $query = \Drupal::entityQuery('node');
   $nids = $query->execute();

  $build = [
   '#theme' => 'item_list',
   '#items' => $nids,
  ];

 return $build;
}