src/Normalizer/EntityNormalizer.php | 31 ++++++++++++++++++++++---------
 1 file changed, 22 insertions(+), 9 deletions(-)

diff --git a/src/Normalizer/EntityNormalizer.php b/src/Normalizer/EntityNormalizer.php
index 1ddc5ab..ec99785 100644
--- a/src/Normalizer/EntityNormalizer.php
+++ b/src/Normalizer/EntityNormalizer.php
@@ -129,7 +129,7 @@ class EntityNormalizer extends NormalizerBase implements DenormalizerInterface {
       $normalization_parts = $cached_normalization_parts->data;
     }
     else {
-      $normalization_parts = $this->doNormalize($resource_type, $entity, $format, $context);
+      $normalization_parts = $this->getPartialNormalization($resource_type, $entity, $format, $context);
       $normalization_parts_cacheability = static::mergeCacheableDependencies($normalization_parts['fields']);
       $cache_tags = Cache::mergeTags($entity->getCacheTags(), $normalization_parts_cacheability->getCacheTags());
       $this->cache->set($cid, $normalization_parts, Cache::PERMANENT, $cache_tags);
@@ -151,17 +151,30 @@ class EntityNormalizer extends NormalizerBase implements DenormalizerInterface {
   }
 
   /**
-   * Does the actual normalization.
+   * Normalizes an entity into a partial normalization.
    *
-   * @todo remove $format & $context
+   * @param \Drupal\Core\Entity\EntityInterface $entity
+   *   The entity to partially normalize.
+   * @param \Drupal\jsonapi\ResourceType\ResourceType $resource_type
+   *   The JSON:API resource type for the given entity.
+   * @param string $format
+   *   Format the normalization result will be encoded as.
+   * @param array $context
+   *   Context options for the normalizer.
+   *
+   * @return array
+   *   An array with two key-value pairs:
+   *   - 'base': array, the base normalization of the entity, that does not
+   *             depend on which sparse fieldset was requested.
+   *   - 'fields': CacheableNormalization for every field on this entity, of
+   *               which a subset will need to be selected depending on the
+   *               requested sparse fieldset.
+   *
+   * @see ::normalize()
    */
-  private function doNormalize(ResourceType $resource_type, EntityInterface $entity, $format = NULL, array $context = []) {
-    // Get the bundle ID of the requested resource. This is used to determine if
-    // this is a bundle level resource or an entity level resource.
-    $bundle = $resource_type->getBundle();
-    $field_names = $this->getFieldNames($entity, $bundle, $resource_type);
+  private function getPartialNormalization(EntityInterface $entity, ResourceType $resource_type, $format = NULL, array $context = []) {
     $normalizer_values = [];
-    foreach ($this->getFields($entity, $bundle, $resource_type) as $field_name => $field) {
+    foreach ($this->getFields($entity, $resource_type->getBundle(), $resource_type) as $field_name => $field) {
       $normalizer_values[$field_name] = $this->serializeField($field, $context, $format);
     }
     // Create the array of normalized fields, starting with the URI.