Drupal 8 - Example how to extract entity values into array with referenced entities

gistfile1.txt

$fields = $entity->getFields();

$entity_values = [];
/** @var \Drupal\Core\Field\FieldItemList $field */
foreach ($fields as $field_id => $field) {
  $entity_values[$field_id] = $field->getValue();

  if (method_exists($field, 'referencedEntities')) {
    $referenced_entities = $field->referencedEntities();

    foreach ($referenced_entities as $index => $referenced_entity) {
      $entity_values[$field_id][$index]['entity'] = $referenced_entity;
    }
  }
}