Code snippet that can be used to sort nodes by title programmatically drupal 8.
$result=[];
$query = \Drupal::entityQuery('node')
->condition('type', 'article')
->sort('title', 'DESC');
$nodes_ids = $query->execute();
if ($nodes_ids) {
foreach ($nodes_ids as $node_id) {
$node = \Drupal\node\Entity\Node::load($node_id);
$result[$node->id()] = $node->getTitle();
}
}
