diff --git a/src/Plugin/facets/processor/ListItemProcessor.php b/src/Plugin/facets/processor/ListItemProcessor.php
index 14cc0f1..a6d6822 100644
--- a/src/Plugin/facets/processor/ListItemProcessor.php
+++ b/src/Plugin/facets/processor/ListItemProcessor.php
@@ -9,9 +9,7 @@
 use Drupal\Core\Field\FieldStorageDefinitionInterface;
 use Drupal\Core\Field\TypedData\FieldItemDataDefinition;
 use Drupal\Core\Plugin\ContainerFactoryPluginInterface;
-use Drupal\facets\Exception\InvalidProcessorException;
 use Drupal\facets\FacetInterface;
-use Drupal\facets\Plugin\facets\facet_source\SearchApiDisplay;
 use Drupal\facets\Processor\BuildProcessorInterface;
 use Drupal\facets\Processor\ProcessorPluginBase;
 use Symfony\Component\DependencyInjection\ContainerInterface;
@@ -94,29 +92,31 @@ public static function create(ContainerInterface $container, array $configuratio
    */
   public function build(FacetInterface $facet, array $results) {
     $field_identifier = $facet->getFieldIdentifier();
-    $entity = 'node';
     $field = FALSE;
     $allowed_values = [];
 
-    // Support multiple entities when using Search API.
-    if ($facet->getFacetSource() instanceof SearchApiDisplay) {
-      /** @var \Drupal\search_api\Entity\Index $index */
-      $index = $facet->getFacetSource()->getIndex();
-      /** @var \Drupal\search_api\Item\Field $field */
-      $field = $index->getField($field_identifier);
-
-      if (!$field->getDatasourceId()) {
-        throw new InvalidProcessorException("This field has no datasource, there is no valid use for this processor with this facet");
-      }
-      $entity = $field->getDatasource()->getEntityTypeId();
+    /** @var \Drupal\Core\TypedData\DataDefinitionInterface $field_definition */
+    $field_definition = $facet->getFacetSource()
+      ->getDataDefinition($facet->getFieldIdentifier());
+    if ($field_definition->getPropertyDefinition('entity') !== NULL) {
+      $entity_type = $field_definition
+        ->getPropertyDefinition('entity')
+        ->getTargetDefinition()
+        ->getEntityTypeId();
     }
+    else {
+      // We don't have a referenced entity as a field, so default to nodes, as
+      // that is the 99% usecase.
+      $entity_type = 'node';
+    }
+
     // If it's an entity base field, we find it in the field definitions.
     // We don't have access to the bundle via SearchApiFacetSourceInterface, so
     // we check the entity's base fields only.
-    $base_fields = $this->entityFieldManager->getFieldDefinitions($entity, '');
+    $base_fields = $this->entityFieldManager->getFieldDefinitions($entity_type, '');
 
     // This only works for configurable fields.
-    $config_entity_name = sprintf('field.storage.%s.%s', $entity, $field_identifier);
+    $config_entity_name = sprintf('field.storage.%s.%s', $entity_type, $field_identifier);
     if (isset($base_fields[$field_identifier])) {
       $field = $base_fields[$field_identifier];
     }
@@ -156,7 +156,7 @@ public function build(FacetInterface $facet, array $results) {
     }
     // If no values are found for the current field, try to see if this is a
     // bundle field.
-    $list_bundles = $this->entityTypeBundleInfo->getBundleInfo($entity);
+    $list_bundles = $this->entityTypeBundleInfo->getBundleInfo($entity_type);
     if (!empty($list_bundles)) {
       foreach ($list_bundles as $key => $bundle) {
         $allowed_values[$key] = $bundle['label'];
diff --git a/tests/src/Unit/Plugin/processor/ListItemProcessorTest.php b/tests/src/Unit/Plugin/processor/ListItemProcessorTest.php
index e478a73..10e4d3f 100644
--- a/tests/src/Unit/Plugin/processor/ListItemProcessorTest.php
+++ b/tests/src/Unit/Plugin/processor/ListItemProcessorTest.php
@@ -2,8 +2,12 @@
 
 namespace Drupal\Tests\facets\Unit\Plugin\processor;
 
+use Drupal\Core\DependencyInjection\ContainerBuilder;
 use Drupal\Core\Entity\EntityTypeBundleInfo;
+use Drupal\Core\TypedData\ComplexDataDefinitionInterface;
 use Drupal\facets\Entity\Facet;
+use Drupal\facets\FacetSource\FacetSourcePluginInterface;
+use Drupal\facets\FacetSource\FacetSourcePluginManager;
 use Drupal\facets\Plugin\facets\processor\ListItemProcessor;
 use Drupal\facets\Result\Result;
 use Drupal\field\Entity\FieldStorageConfig;
@@ -57,7 +61,35 @@ protected function setUp() {
       ->disableOriginalConstructor()
       ->getMock();
 
+    // Create a search api based facet source and make the property definition
+    // return null.
+    $data_definition = $this->getMock(ComplexDataDefinitionInterface::class);
+    $data_definition->expects($this->any())
+      ->method('getPropertyDefinition')
+      ->willReturn(NULL);
+    $facet_source = $this->getMockBuilder(FacetSourcePluginInterface::class)
+      ->disableOriginalConstructor()
+      ->getMock();
+    $facet_source->expects($this->any())
+      ->method('getDataDefinition')
+      ->willReturn($data_definition);
+
+    // Add the plugin manager and add
+    $pluginManager = $this->getMockBuilder(FacetSourcePluginManager::class)
+      ->disableOriginalConstructor()
+      ->getMock();
+    $pluginManager->expects($this->any())
+      ->method('hasDefinition')
+      ->willReturn(TRUE);
+    $pluginManager->expects($this->any())
+      ->method('createInstance')
+      ->willReturn($facet_source);
+
     $this->processor = new ListItemProcessor([], 'list_item', [], $config_manager, $entity_field_manager, $entity_type_bundle_info);
+
+    $container = new ContainerBuilder();
+    $container->set('plugin.manager.facets.facet_source', $pluginManager);
+    \Drupal::setContainer($container);
   }
 
   /**
@@ -90,12 +122,14 @@ public function testBuildConfigurableField() {
     // Config entity field facet.
     $module_field_facet = new Facet([], 'facets_facet');
     $module_field_facet->setFieldIdentifier('test_facet');
+    $module_field_facet->setFacetSourceId('llama_source');
     $module_field_facet->setResults($this->results);
     $module_field_facet->addProcessor([
       'processor_id' => 'list_item',
       'weights' => [],
       'settings' => [],
     ]);
+
     /* @var \Drupal\facets\Result\Result[] $module_field_facet- */
     $module_field_results = $processor->build($module_field_facet, $this->results);
 
@@ -133,6 +167,7 @@ public function testBuildBundle() {
     // Config entity field facet.
     $module_field_facet = new Facet([], 'facets_facet');
     $module_field_facet->setFieldIdentifier('test_facet');
+    $module_field_facet->setFacetSourceId('llama_source');
     $module_field_facet->setResults($this->results);
     $module_field_facet->addProcessor([
       'processor_id' => 'list_item',
@@ -179,6 +214,7 @@ public function testBuildBaseField() {
     // Base prop facet.
     $base_prop_facet = new Facet([], 'facets_facet');
     $base_prop_facet->setFieldIdentifier('test_facet_baseprop');
+    $base_prop_facet->setFacetSourceId('llama_source');
     $base_prop_facet->setResults($this->results);
     $base_prop_facet->addProcessor([
       'processor_id' => 'list_item',