Check if a node exists by node title using Entity Field Query (EFQ)

checkNodeExistsByTitle.php

<? php

/**
*  This Drupal 7 helper function can look up if a node exists and is useful
*  if adding nodes in a postImport() method on a migration or
*  if needing to avoid duplicates or relate nodes.
*/

public function checkNodeExistsByTitle($title) {
    $query = new EntityFieldQuery();
    $entities = $query->entityCondition('entity_type', 'node')
      ->propertyCondition('type', 'topic')
      ->propertyCondition('title', $title)
      ->range(0, 1)
      ->execute();
    return $entities;
  }