D728: Task-06 Update nodes programatically

lotus.module

<?php 

use Drupal\node\Entity\Node;
use Drupal\user\Entity\User;

/**
 * Implements hook_ENTITY_TYPE_update().
 * If a user has a Role named 'moderated',
 * append the words 'MODERATED USER' to titles of
 * all the nodes authored by the user
 */

function lotus_user_update(\Drupal\Core\Entity\EntityInterface $entity){
  $user = User::load($entity->id());
  $role = $user->hasRole('moderated');
  if($role){
    $query = \Drupal::entityQuery('node')
      ->condition('uid', $user->id());
    $nids = $query->execute();
    $nodes = Node::loadMultiple($nids);
    foreach($nodes as $node) {
      $old_title = $node->title->value;
      if(strpos($old_title,'(MODERATED USER)') == FALSE) {
        $node->set("title",  $old_title . " (MODERATED USER)");
        $node->save();
      }
    }
    drupal_set_message('All nodes of the user updated');
  }
}