diff --git a/src/ResourceType/ResourceFieldFactory.php b/src/ResourceType/ResourceFieldFactory.php
index eb2ec20..06f83e9 100644
--- a/src/ResourceType/ResourceFieldFactory.php
+++ b/src/ResourceType/ResourceFieldFactory.php
@@ -26,6 +26,13 @@ class ResourceFieldFactory {
    */
   protected $entityFieldManager;
 
+  /**
+   * An index of maps of public field names to internal field names.
+   *
+   * @var array
+   */
+  protected $fieldMappings;
+
   /**
    * ResourceFieldFactory constructor.
    *
@@ -36,6 +43,29 @@ class ResourceFieldFactory {
     $this->entityFieldManager = $entity_field_manager;
   }
 
+  /**
+   * Gets all resource fields for a given entity type and bundle.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+   *   The entity type for which to get all field names.
+   * @param string $bundle
+   *   The bundle for which to get all field names.
+   *
+   * @return mixed[]
+   *   An array of resource fields (or FALSE if the field is disabled) keyed by
+   *   internal field name.
+   */
+  public function createResourceFields(EntityTypeInterface $entity_type, $bundle) {
+    return array_reduce($this->getAllFieldNames($entity_type, $bundle), function ($fields, $internal_field_name) use ($entity_type, $bundle) {
+      $mapping = $this->getFieldMappingByInternalFieldName($entity_type, $bundle, $internal_field_name);
+      // If the mapping is FALSE, the field is disabled.
+      $fields[$internal_field_name] = $mapping !== FALSE
+        ? $this->createResourceField($entity_type, $bundle, $internal_field_name, is_string($mapping) ? $mapping : NULL)
+        : FALSE;
+      return $fields;
+    }, []);
+  }
+
   /**
    * Creates a ResourceFieldInterface object for a given field.
    *
@@ -146,4 +176,124 @@ class ResourceFieldFactory {
     return $data_definition instanceof DataReferenceTargetDefinition;
   }
 
+  /**
+   * Get the public field alias for a given internal field.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+   *   The entity type to which the field belongs.
+   * @param $bundle
+   *   The bundle to which the field belongs.
+   * @param $internal_field_name
+   *   The internal field name.
+   *
+   * @return string
+   */
+  protected function getFieldMappingByInternalFieldName(EntityTypeInterface $entity_type, $bundle, $internal_field_name) {
+    if (!isset($this->fieldMappings[$entity_type->id()][$bundle])) {
+      $this->fieldMappings[$entity_type->id()][$bundle] = static::getFieldMapping($entity_type, $bundle);
+    }
+    return $this->fieldMappings[$entity_type->id()][$bundle][$internal_field_name];
+  }
+
+  /**
+   * Gets all field names for a given entity type and bundle.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+   *   The entity type for which to get all field names.
+   * @param string $bundle
+   *   The bundle for which to get all field names.
+   *
+   * @return string[]
+   *   All field names.
+   */
+  public function getAllFieldNames(EntityTypeInterface $entity_type, $bundle) {
+    if ($entity_type instanceof ContentEntityTypeInterface) {
+      return array_keys($this->entityFieldManager->getFieldDefinitions($entity_type->id(), $bundle));
+    }
+    elseif ($entity_type instanceof ConfigEntityTypeInterface) {
+      // @todo Uncomment the first line, remove everything else once https://www.drupal.org/project/drupal/issues/2483407 lands.
+      // return array_keys($entity_type->getPropertiesToExport());
+      $export_properties = $entity_type->getPropertiesToExport();
+      if ($export_properties !== NULL) {
+        return array_keys($export_properties);
+      }
+      else {
+        return ['id', 'type', 'uuid', '_core'];
+      }
+    }
+    else {
+      throw new \LogicException("Only content and config entity types are supported.");
+    }
+  }
+
+  /**
+   * Gets the field mapping for the given field names and entity type + bundle.
+   *
+   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+   *   The entity type for which to get the field mapping.
+   * @param string $bundle
+   *   The bundle to assess.
+   *
+   * @return array
+   *   An array with:
+   *   - keys are (real/internal) field names
+   *   - values are either FALSE (indicating the field is not exposed despite
+   *     not being internal), TRUE (indicating the field should be exposed under
+   *     its internal name) or a string (indicating the field should not be
+   *     exposed using its internal name, but the name specified in the string)
+   */
+  protected function getFieldMapping(EntityTypeInterface $entity_type, $bundle) {
+    $field_names = $this->getAllFieldNames($entity_type, $bundle);
+    assert($entity_type instanceof ContentEntityTypeInterface || $entity_type instanceof ConfigEntityTypeInterface);
+    assert(is_string($bundle) && !empty($bundle), 'A bundle ID is required. Bundleless entity types should pass the entity type ID again.');
+
+    $mapping = [];
+
+    // JSON:API resource identifier objects are sufficient to identify
+    // entities. By exposing all fields as attributes, we expose unwanted,
+    // confusing or duplicate information:
+    // - exposing an entity's ID (which is not a UUID) is bad, but it's
+    //   necessary for certain Drupal-coupled clients, so we alias it.
+    // - exposing its UUID as an attribute is useless (it's already part of
+    //   the mandatory "id" attribute in JSON:API)
+    // - exposing its revision ID as an attribute will compete with any profile
+    //   defined meta members used for resource object versioning.
+    // @see http://jsonapi.org/format/#document-resource-identifier-objects
+    $mapping[$entity_type->getKey('uuid')] = FALSE;
+    if ($id_field_name = $entity_type->getKey('id')) {
+      $mapping[$id_field_name] = "drupal_internal__$id_field_name";
+    }
+    if ($entity_type->isRevisionable() && ($revision_id_field_name = $entity_type->getKey('revision'))) {
+      $mapping[$revision_id_field_name] = "drupal_internal__$revision_id_field_name";
+    }
+    if ($entity_type instanceof ConfigEntityTypeInterface) {
+      // The '_core' key is reserved by Drupal core to handle complex edge cases
+      // correctly. Data in the '_core' key is irrelevant to clients reading
+      // configuration, and is not allowed to be set by clients writing
+      // configuration: it is for Drupal core only, and managed by Drupal core.
+      // @see https://www.drupal.org/node/2653358
+      $mapping['_core'] = FALSE;
+    }
+
+    // For all other fields, use their internal field name also as their public
+    // field name.  Unless they're called "id" or "type": those names are
+    // reserved by the JSON:API spec.
+    // @see http://jsonapi.or
+    foreach (array_diff($field_names, array_keys($mapping)) as $field_name) {
+      if ($field_name === 'id' || $field_name === 'type') {
+        $alias = $entity_type->id() . '_' . $field_name;
+        if (isset($field_names[$alias])) {
+          throw new \LogicException('The generated alias conflicts with an existing field. Please report this in the JSON:API issue queue!');
+        }
+        $mapping[$field_name] = $alias;
+        continue;
+      }
+
+      // The default, which applies to most fields: expose as-is.
+      $mapping[$field_name] = TRUE;
+    }
+
+    return $mapping;
+  }
+
 }
diff --git a/src/ResourceType/ResourceType.php b/src/ResourceType/ResourceType.php
index 2ad6802..86da864 100644
--- a/src/ResourceType/ResourceType.php
+++ b/src/ResourceType/ResourceType.php
@@ -2,11 +2,6 @@
 
 namespace Drupal\jsonapi\ResourceType;
 
-use Drupal\Component\Assertion\Inspector;
-use Drupal\Core\Config\Entity\ConfigEntityTypeInterface;
-use Drupal\Core\Entity\ContentEntityTypeInterface;
-use Drupal\Core\Entity\EntityTypeInterface;
-
 /**
  * Value object containing all metadata for a JSON:API resource type.
  *
@@ -24,11 +19,11 @@ use Drupal\Core\Entity\EntityTypeInterface;
 class ResourceType {
 
   /**
-   * The entity type.
+   * The entity type ID.
    *
-   * @var \Drupal\Core\Entity\EntityTypeInterface
+   * @var string
    */
-  protected $entityType;
+  protected $entityTypeId;
 
   /**
    * The bundle ID.
@@ -80,50 +75,19 @@ class ResourceType {
   protected $isVersionable;
 
   /**
-   * The list of fields on the underlying entity type + bundle.
+   * The resource fields keyed by internal field name.
    *
-   * @var string[]
+   * @var \Drupal\jsonapi\ResourceType\ResourceFieldInterface[]
    */
   protected $fields;
 
   /**
-   * The list of disabled fields. Disabled by default: uuid, id, type.
-   *
-   * @var string[]
-   *
-   * @see \Drupal\jsonapi\ResourceType\ResourceTypeRepository::getFieldMapping()
-   */
-  protected $disabledFields;
-
-  /**
-   * The mapping for field aliases: keys=internal names, values=public names.
+   * A map of public field names to internal field names.
    *
    * @var string[]
    */
   protected $fieldMapping;
 
-  /**
-   * The inverse of $fieldMapping.
-   *
-   * @var string[]
-   */
-  protected $invertedFieldMapping;
-
-
-  /**
-   * The field definitions for this resource type.
-   *
-   * @var \Drupal\Core\Field\FieldDefinitionInterface[]
-   */
-  protected $fieldDefinitions;
-
-  /**
-   * The resource fields keyed by public field name.
-   *
-   * @var \Drupal\jsonapi\ResourceType\ResourceFieldInterface[]
-   */
-  protected $resourceFields;
-
   /**
    * Gets the entity type ID.
    *
@@ -133,7 +97,7 @@ class ResourceType {
    * @see \Drupal\Core\Entity\EntityInterface::getEntityTypeId
    */
   public function getEntityTypeId() {
-    return $this->entityType->id();
+    return $this->entityTypeId;
   }
 
   /**
@@ -178,7 +142,7 @@ class ResourceType {
    * @return \Drupal\jsonapi\ResourceType\ResourceFieldInterface
    */
   public function getFieldByName($field_name) {
-    return $this->resourceFields[$field_name];
+    return $this->fields[$this->getInternalName($field_name)];
   }
 
   /**
@@ -188,7 +152,7 @@ class ResourceType {
    *   The fields.
    */
   public function getResourceFields() {
-    return $this->resourceFields;
+    return array_values(array_filter($this->fields));
   }
 
   /**
@@ -230,9 +194,7 @@ class ResourceType {
    */
   public function getPublicName($field_name) {
     // By default the entity field name is the public field name.
-    return isset($this->fieldMapping[$field_name])
-      ? $this->fieldMapping[$field_name]
-      : $field_name;
+    return ($field = $this->getFieldByName($field_name)) ? $field->getPublicFieldName() : $field_name;
   }
 
   /**
@@ -246,8 +208,8 @@ class ResourceType {
    */
   public function getInternalName($field_name) {
     // By default the entity field name is the public field name.
-    return isset($this->invertedFieldMapping[$field_name])
-      ? $this->invertedFieldMapping[$field_name]
+    return isset($this->fieldMapping[$field_name])
+      ? $this->fieldMapping[$field_name]
       : $field_name;
   }
 
@@ -269,7 +231,7 @@ class ResourceType {
    *   otherwise.
    */
   public function hasField($field_name) {
-    return in_array($field_name, $this->fields, TRUE);
+    return isset($this->fields[$field_name]);
   }
 
   /**
@@ -286,7 +248,7 @@ class ResourceType {
    *   of the data model. FALSE otherwise.
    */
   public function isFieldEnabled($field_name) {
-    return $this->hasField($field_name) && !in_array($field_name, $this->disabledFields, TRUE);
+    return $this->hasField($field_name) && $this->fields[$field_name] !== FALSE;
   }
 
   /**
@@ -363,14 +325,12 @@ class ResourceType {
   /**
    * Instantiates a ResourceType object.
    *
-   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
+   * @param string $entity_type_id
    *   An entity type ID.
    * @param string $bundle
    *   A bundle.
    * @param string $deserialization_target_class
    *   The deserialization target class.
-   * @param array $field_definitions
-   *   The field definitions for this resource type.
    * @param bool $internal
    *   (optional) Whether the resource type should be internal.
    * @param bool $is_locatable
@@ -379,12 +339,15 @@ class ResourceType {
    *   (optional) Whether the resource type is mutable.
    * @param bool $is_versionable
    *   (optional) Whether the resource type is versionable.
+   * @param array $fields
+   *   An array of resource fields keyed by internal field name. An array value
+   *   of FALSE means the field is disabled.
    */
-  public function __construct(EntityTypeInterface $entity_type, $bundle, $deserialization_target_class, array $field_definitions, $internal = FALSE, $is_locatable = TRUE, $is_mutable = TRUE, $is_versionable = FALSE) {
-    $this->entityType = $entity_type;
+  public function __construct($entity_type_id, $bundle, $deserialization_target_class, $internal = FALSE, $is_locatable = TRUE, $is_mutable = TRUE, $is_versionable = FALSE, array $fields = []) {
+    $this->entityTypeId = $entity_type_id;
     $this->bundle = $bundle;
+    $this->fields = $fields;
     $this->deserializationTargetClass = $deserialization_target_class;
-    $this->fieldDefinitions = $field_definitions;
     $this->internal = $internal;
     $this->isLocatable = $is_locatable;
     $this->isMutable = $is_mutable;
@@ -392,32 +355,11 @@ class ResourceType {
 
     $this->typeName = $this->bundle === '?'
       ? 'unknown'
-      : sprintf('%s--%s', $this->entityType->id(), $this->bundle);
-
-    $field_mapping = static::getFieldMapping(
-      $this->getAllFieldNames(),
-      $entity_type,
-      $bundle
-    );
-    $this->fields = array_keys($field_mapping);
-    $this->disabledFields = array_keys(array_filter($field_mapping, function ($v) {
-      return $v === FALSE;
-    }));
-    $this->fieldMapping = array_filter($field_mapping, 'is_string');
-    $this->invertedFieldMapping = array_flip($this->fieldMapping);
-    $this->resourceFields = [];
-    foreach ($field_mapping as $field_name => $alias) {
-      if ($alias === FALSE) {
-        continue;
-      }
-      $resource_field_factory = \Drupal::service('jsonapi.resource_field.factory');
-      assert($resource_field_factory instanceof TypedResourceFieldFactory);
-      $this->resourceFields[$field_name] = $resource_field_factory->createResourceField(
-        $this->entityType,
-        $this->bundle,
-        $field_name,
-        $alias
-      );
+      : sprintf('%s--%s', $this->entityTypeId, $this->bundle);
+
+    foreach ($this->fields as $internal_field_name => $field) {
+      $public_field_name = $field instanceof ResourceFieldInterface ? $field->getPublicFieldName() : $internal_field_name;
+      $this->fieldMapping[$public_field_name] = $internal_field_name;
     }
   }
 
@@ -432,9 +374,7 @@ class ResourceType {
    */
   public function setRelatableResourceTypes(array $relatable_resource_types) {
     $this->relatableResourceTypes = $relatable_resource_types;
-    $rels = array_filter($this->resourceFields, function (ResourceFieldInterface $field) {
-      return $field instanceof ResourceRelationship;
-    });
+    $rels = $this->getResourceRelationships();
     array_walk($rels, function (ResourceRelationship $rel) use ($relatable_resource_types) {
       $relatable = empty($relatable_resource_types[$rel->getPublicFieldName()])
         ? []
@@ -470,10 +410,9 @@ class ResourceType {
    * @see self::getRelatableResourceTypes()
    */
   public function getRelatableResourceTypesByField($field_name) {
-    $relatable_resource_types = $this->getRelatableResourceTypes();
-    return isset($relatable_resource_types[$field_name]) ?
-      $relatable_resource_types[$field_name] :
-      [];
+    $field = $this->getFieldByName($field_name);
+    assert($field instanceof ResourceRelationship);
+    return $field->getRelatableResourceTypes();
   }
 
   /**
@@ -488,103 +427,4 @@ class ResourceType {
     return sprintf('/%s/%s', $this->getEntityTypeId(), $this->getBundle());
   }
 
-  /**
-   * Gets all field names for a given entity type and bundle.
-   *
-   * @return string[]
-   *   All field names.
-   */
-  protected function getAllFieldNames() {
-    $entity_type = $this->entityType;
-    if ($entity_type instanceof ContentEntityTypeInterface) {
-      return array_keys($this->fieldDefinitions);
-    }
-    elseif ($entity_type instanceof ConfigEntityTypeInterface) {
-      // @todo Uncomment the first line, remove everything else once https://www.drupal.org/project/drupal/issues/2483407 lands.
-      // return array_keys($entity_type->getPropertiesToExport());
-      $export_properties = $entity_type->getPropertiesToExport();
-      if ($export_properties !== NULL) {
-        return array_keys($export_properties);
-      }
-      else {
-        return ['id', 'type', 'uuid', '_core'];
-      }
-    }
-    else {
-      throw new \LogicException("Only content and config entity types are supported.");
-    }
-  }
-
-  /**
-   * Gets the field mapping for the given field names and entity type + bundle.
-   *
-   * @param string[] $field_names
-   *   All field names on a bundle of the given entity type.
-   * @param \Drupal\Core\Entity\EntityTypeInterface $entity_type
-   *   The entity type for which to get the field mapping.
-   * @param string $bundle
-   *   The bundle to assess.
-   *
-   * @return array
-   *   An array with:
-   *   - keys are (real/internal) field names
-   *   - values are either FALSE (indicating the field is not exposed despite
-   *     not being internal), TRUE (indicating the field should be exposed under
-   *     its internal name) or a string (indicating the field should not be
-   *     exposed using its internal name, but the name specified in the string)
-   */
-  protected static function getFieldMapping(array $field_names, EntityTypeInterface $entity_type, $bundle) {
-    assert(Inspector::assertAllStrings($field_names));
-    assert($entity_type instanceof ContentEntityTypeInterface || $entity_type instanceof ConfigEntityTypeInterface);
-    assert(is_string($bundle) && !empty($bundle), 'A bundle ID is required. Bundleless entity types should pass the entity type ID again.');
-
-    $mapping = [];
-
-    // JSON:API resource identifier objects are sufficient to identify
-    // entities. By exposing all fields as attributes, we expose unwanted,
-    // confusing or duplicate information:
-    // - exposing an entity's ID (which is not a UUID) is bad, but it's
-    //   necessary for certain Drupal-coupled clients, so we alias it.
-    // - exposing its UUID as an attribute is useless (it's already part of
-    //   the mandatory "id" attribute in JSON:API)
-    // - exposing its revision ID as an attribute will compete with any profile
-    //   defined meta members used for resource object versioning.
-    // @see http://jsonapi.org/format/#document-resource-identifier-objects
-    $mapping[$entity_type->getKey('uuid')] = FALSE;
-    if ($id_field_name = $entity_type->getKey('id')) {
-      $mapping[$id_field_name] = "drupal_internal__$id_field_name";
-    }
-    if ($entity_type->isRevisionable() && ($revision_id_field_name = $entity_type->getKey('revision'))) {
-      $mapping[$revision_id_field_name] = "drupal_internal__$revision_id_field_name";
-    }
-    if ($entity_type instanceof ConfigEntityTypeInterface) {
-      // The '_core' key is reserved by Drupal core to handle complex edge cases
-      // correctly. Data in the '_core' key is irrelevant to clients reading
-      // configuration, and is not allowed to be set by clients writing
-      // configuration: it is for Drupal core only, and managed by Drupal core.
-      // @see https://www.drupal.org/node/2653358
-      $mapping['_core'] = FALSE;
-    }
-
-    // For all other fields, use their internal field name also as their public
-    // field name.  Unless they're called "id" or "type": those names are
-    // reserved by the JSON:API spec.
-    // @see http://jsonapi.org/format/#document-resource-object-fields
-    foreach (array_diff($field_names, array_keys($mapping)) as $field_name) {
-      if ($field_name === 'id' || $field_name === 'type') {
-        $alias = $entity_type->id() . '_' . $field_name;
-        if (isset($field_name[$alias])) {
-          throw new \LogicException('The generated alias conflicts with an existing field. Please report this in the JSON:API issue queue!');
-        }
-        $mapping[$field_name] = $alias;
-        continue;
-      }
-
-      // The default, which applies to most fields: expose as-is.
-      $mapping[$field_name] = TRUE;
-    }
-
-    return $mapping;
-  }
-
 }
diff --git a/src/ResourceType/ResourceTypeRepository.php b/src/ResourceType/ResourceTypeRepository.php
index 2a3eb9f..a04fc56 100644
--- a/src/ResourceType/ResourceTypeRepository.php
+++ b/src/ResourceType/ResourceTypeRepository.php
@@ -57,6 +57,13 @@ class ResourceTypeRepository implements ResourceTypeRepositoryInterface {
    */
   protected $entityFieldManager;
 
+  /**
+   * The JSON:API resource field factory.
+   *
+   * @var \Drupal\jsonapi\ResourceType\ResourceFieldFactory
+   */
+  protected $resourceFieldFactory;
+
   /**
    * The static cache backend.
    *
@@ -87,6 +94,7 @@ class ResourceTypeRepository implements ResourceTypeRepositoryInterface {
     $this->entityTypeManager = $entity_type_manager;
     $this->entityTypeBundleInfo = $entity_bundle_info;
     $this->entityFieldManager = $entity_field_manager;
+    $this->resourceFieldFactory = $resource_field_factory;
     $this->staticCache = $static_cache;
   }
 
@@ -123,22 +131,15 @@ class ResourceTypeRepository implements ResourceTypeRepositoryInterface {
    *   A JSON:API resource type.
    */
   protected function createResourceType(EntityTypeInterface $entity_type, $bundle) {
-    $field_definitions = [];
-    if ($entity_type->entityClassImplements(FieldableEntityInterface::class)) {
-      $field_definitions = $this->entityFieldManager->getFieldDefinitions(
-        $entity_type->id(),
-        $bundle
-      );
-    }
     return new ResourceType(
-      $entity_type,
+      $entity_type->id(),
       $bundle,
       $entity_type->getClass(),
-      $field_definitions,
       $entity_type->isInternal(),
       static::isLocatableResourceType($entity_type, $bundle),
       static::isMutableResourceType($entity_type, $bundle),
-      static::isVersionableResourceType($entity_type)
+      static::isVersionableResourceType($entity_type),
+      $this->resourceFieldFactory->createResourceFields($entity_type, $bundle)
     );
   }
 
@@ -298,19 +299,6 @@ class ResourceTypeRepository implements ResourceTypeRepositoryInterface {
     }, $target_bundles);
   }
 
-  /**
-   * Gets all bundle IDs for a given entity type.
-   *
-   * @param string $entity_type_id
-   *   The entity type for which to get bundles.
-   *
-   * @return string[]
-   *   The bundle IDs.
-   */
-  protected function getAllBundlesForEntityType($entity_type_id) {
-    return array_keys($this->entityTypeBundleInfo->getBundleInfo($entity_type_id));
-  }
-
   /**
    * Determines if a given field definition is a reference field.
    *
@@ -322,7 +310,20 @@ class ResourceTypeRepository implements ResourceTypeRepositoryInterface {
    *   otherwise.
    */
   protected function isReferenceFieldDefinition(FieldDefinitionInterface $field_definition) {
-    return ResourceFieldFactory::isReference($field_definition->getItemDefinition());
+    return ResourceFieldFactory::isReference($field_definition);
+  }
+
+  /**
+   * Gets all bundle IDs for a given entity type.
+   *
+   * @param string $entity_type_id
+   *   The entity type for which to get bundles.
+   *
+   * @return string[]
+   *   The bundle IDs.
+   */
+  protected function getAllBundlesForEntityType($entity_type_id) {
+    return array_keys($this->entityTypeBundleInfo->getBundleInfo($entity_type_id));
   }
 
 }
diff --git a/tests/modules/jsonapi_test_collection_count/src/ResourceType/CountableResourceTypeRepository.php b/tests/modules/jsonapi_test_collection_count/src/ResourceType/CountableResourceTypeRepository.php
index 33c9c1a..67a3012 100644
--- a/tests/modules/jsonapi_test_collection_count/src/ResourceType/CountableResourceTypeRepository.php
+++ b/tests/modules/jsonapi_test_collection_count/src/ResourceType/CountableResourceTypeRepository.php
@@ -14,7 +14,6 @@ class CountableResourceTypeRepository extends ResourceTypeRepository {
    * {@inheritdoc}
    */
   protected function createResourceType(EntityTypeInterface $entity_type, $bundle) {
-    $raw_fields = $this->getAllFieldNames($entity_type, $bundle);
     return new CountableResourceType(
       $entity_type->id(),
       $bundle,
@@ -22,7 +21,8 @@ class CountableResourceTypeRepository extends ResourceTypeRepository {
       $entity_type->isInternal(),
       static::isLocatableResourceType($entity_type, $bundle),
       static::isMutableResourceType($entity_type, $bundle),
-      static::getFieldMapping($raw_fields, $entity_type, $bundle)
+      static::isVersionableResourceType($entity_type),
+      $this->resourceFieldFactory->createResourceFields($entity_type, $bundle)
     );
   }
 
diff --git a/tests/modules/jsonapi_test_field_aliasing/jsonapi_test_field_aliasing.services.yml b/tests/modules/jsonapi_test_field_aliasing/jsonapi_test_field_aliasing.services.yml
index 184daa4..c3c4140 100644
--- a/tests/modules/jsonapi_test_field_aliasing/jsonapi_test_field_aliasing.services.yml
+++ b/tests/modules/jsonapi_test_field_aliasing/jsonapi_test_field_aliasing.services.yml
@@ -1,6 +1,6 @@
 services:
-  jsonapi.resource_type.repository.jsonapi_test_field_aliasing:
-    class: Drupal\jsonapi_test_field_aliasing\ResourceType\AliasingResourceTypeRepository
+  jsonapi.resource_field.factory.jsonapi_test_field_aliasing:
+    class: Drupal\jsonapi_test_field_aliasing\ResourceType\AliasingResourceFieldFactory
     public: false
-    decorates: jsonapi.resource_type.repository
-    parent: jsonapi.resource_type.repository
+    decorates: jsonapi.resource_field.factory
+    parent: jsonapi.resource_field.factory
diff --git a/tests/modules/jsonapi_test_field_aliasing/src/ResourceType/AliasingResourceTypeRepository.php b/tests/modules/jsonapi_test_field_aliasing/src/ResourceType/AliasingResourceFieldFactory.php
similarity index 36%
rename from tests/modules/jsonapi_test_field_aliasing/src/ResourceType/AliasingResourceTypeRepository.php
rename to tests/modules/jsonapi_test_field_aliasing/src/ResourceType/AliasingResourceFieldFactory.php
index 59850da..2765840 100644
--- a/tests/modules/jsonapi_test_field_aliasing/src/ResourceType/AliasingResourceTypeRepository.php
+++ b/tests/modules/jsonapi_test_field_aliasing/src/ResourceType/AliasingResourceFieldFactory.php
@@ -3,21 +3,21 @@
 namespace Drupal\jsonapi_test_field_aliasing\ResourceType;
 
 use Drupal\Core\Entity\EntityTypeInterface;
-use Drupal\jsonapi\ResourceType\ResourceTypeRepository;
+use Drupal\jsonapi\ResourceType\ResourceFieldFactory;
 
 /**
  * Provides a repository of JSON:API resource types with aliasable field names.
  */
-class AliasingResourceTypeRepository extends ResourceTypeRepository {
+class AliasingResourceFieldFactory extends ResourceFieldFactory {
 
   /**
    * {@inheritdoc}
    */
-  protected static function getFieldMapping(array $field_names, EntityTypeInterface $entity_type, $bundle) {
-    $mapping = parent::getFieldMapping($field_names, $entity_type, $bundle);
-    foreach ($field_names as $field_name) {
-      if (strpos($field_name, 'field_test_alias_') === 0) {
-        $mapping[$field_name] = 'field_test_alias';
+  protected function getFieldMapping(EntityTypeInterface $entity_type, $bundle) {
+    $mapping = parent::getFieldMapping($entity_type, $bundle);
+    foreach ($mapping as $internal_field_name => $mapped_field_name) {
+      if (strpos($internal_field_name, 'field_test_alias_') === 0) {
+        $mapping[$internal_field_name] = 'field_test_alias';
       }
     }
     return $mapping;