diff --git a/src/Plugin/better_exposed_filters/filter/Facets.php b/src/Plugin/better_exposed_filters/filter/Facets.php
index 0f059e685070efdf6aad6e79ad48f7304f962840..d642956e05a4360a0039b89982df789abab5a977 100644
--- a/src/Plugin/better_exposed_filters/filter/Facets.php
+++ b/src/Plugin/better_exposed_filters/filter/Facets.php
@@ -20,7 +20,7 @@ class Facets extends FilterWidgetBase {
    * {@inheritdoc}
    */
   public function exposedFormAlter(array &$form, FormStateInterface $form_state) {
-    if ($form_state->facets_not_built ?? FALSE) {
+    if ($form_state->get('facets_not_built') ?? FALSE) {
       return;
     }
 
diff --git a/src/Plugin/facets/processor/DisplayValueWidgetOrderProcessor.php b/src/Plugin/facets/processor/DisplayValueWidgetOrderProcessor.php
index c1485806d5b69b7f7e640799b46be4229b83b82b..f92f46c2e9e9a5d020898497c184c3a117e9973e 100644
--- a/src/Plugin/facets/processor/DisplayValueWidgetOrderProcessor.php
+++ b/src/Plugin/facets/processor/DisplayValueWidgetOrderProcessor.php
@@ -68,18 +68,18 @@ class DisplayValueWidgetOrderProcessor extends SortProcessorPluginBase implement
    */
   public function sortResults(Result $a, Result $b) {
     // Get the transliterate values only once.
-    if (!isset($a->transliterateDisplayValue)) {
-      $a->transliterateDisplayValue = $this->transliteration->removeDiacritics($a->getDisplayValue());
+    if (!$a->get('transliterateDisplayValue')) {
+      $a->set('transliterateDisplayValue', $this->transliteration->removeDiacritics($a->getDisplayValue()));
     }
-    if (!isset($b->transliterateDisplayValue)) {
-      $b->transliterateDisplayValue = $this->transliteration->removeDiacritics($b->getDisplayValue());
+    if (!$b->get('transliterateDisplayValue')) {
+      $b->set('transliterateDisplayValue', $this->transliteration->removeDiacritics($b->getDisplayValue()));
     }
 
     // Return the sort value.
-    if ($a->transliterateDisplayValue == $b->transliterateDisplayValue) {
+    if ($a->get('transliterateDisplayValue') == $b->get('transliterateDisplayValue')) {
       return 0;
     }
-    return strnatcasecmp($a->transliterateDisplayValue, $b->transliterateDisplayValue);
+    return strnatcasecmp($a->get('transliterateDisplayValue'), $b->get('transliterateDisplayValue'));
   }
 
 }
diff --git a/src/Plugin/facets/processor/TermWeightWidgetOrderProcessor.php b/src/Plugin/facets/processor/TermWeightWidgetOrderProcessor.php
index bedfb2ba26add593c25f3ebe06614ad6a2d11d87..3b56512a1bb30e70742938dd50315e4896703910 100644
--- a/src/Plugin/facets/processor/TermWeightWidgetOrderProcessor.php
+++ b/src/Plugin/facets/processor/TermWeightWidgetOrderProcessor.php
@@ -71,38 +71,38 @@ class TermWeightWidgetOrderProcessor extends SortProcessorPluginBase implements
    */
   public function sortResults(Result $a, Result $b) {
     // Get the term weight once.
-    if (!isset($a->termWeight) || !isset($b->termWeight)) {
+    if ($a->get('termWeight') === NULL || $b->get('termWeight') === NULL) {
       $ids = [];
-      if (!isset($a->termWeight)) {
+      if ($a->get('termWeight') === NULL) {
         $a_raw = $a->getRawValue();
         $ids[] = $a_raw;
       }
-      if (!isset($b->termWeight)) {
+      if ($b->get('termWeight') === NULL) {
         $b_raw = $b->getRawValue();
         $ids[] = $b_raw;
       }
       $entities = $this->entityTypeManager
         ->getStorage('taxonomy_term')
         ->loadMultiple($ids);
-      if (!isset($a->termWeight)) {
+      if ($a->get('termWeight') === NULL) {
         if (empty($entities[$a_raw])) {
           return 0;
         }
-        $a->termWeight = $entities[$a_raw]->getWeight();
+        $a->set('termWeight', $entities[$a_raw]->getWeight());
       }
-      if (!isset($b->termWeight)) {
+      if ($b->get('termWeight') === NULL) {
         if (empty($entities[$b_raw])) {
           return 0;
         }
-        $b->termWeight = $entities[$b_raw]->getWeight();
+        $b->set('termWeight', $entities[$b_raw]->getWeight());
       }
     }
 
     // Return the sort value.
-    if ($a->termWeight === $b->termWeight) {
+    if ($a->get('termWeight') === $b->get('termWeight')) {
       return 0;
     }
-    return ($a->termWeight < $b->termWeight) ? -1 : 1;
+    return ($a->get('termWeight') < $b->get('termWeight')) ? -1 : 1;
   }
 
   /**
diff --git a/src/Plugin/views/filter/FacetsFilter.php b/src/Plugin/views/filter/FacetsFilter.php
index bd44301da27ce845172c0022a3abb08dc4b112a2..186626df364ead46ad4e06cf08e472ed1de932c3 100644
--- a/src/Plugin/views/filter/FacetsFilter.php
+++ b/src/Plugin/views/filter/FacetsFilter.php
@@ -111,7 +111,7 @@ class FacetsFilter extends FilterPluginBase {
     static $is_processing = NULL;
 
     if ($is_processing) {
-      $form_state->facets_not_built = TRUE;
+      $form_state->set('facets_not_built', TRUE);
       $form['value'] = [];
       return;
     }
diff --git a/src/Result/Result.php b/src/Result/Result.php
index 334dc68559ba310b8743a188a66a2f1075e059b1..40a0c2e578afd9984fea7c47de9efbb42b07ca18 100644
--- a/src/Result/Result.php
+++ b/src/Result/Result.php
@@ -2,6 +2,7 @@
 
 namespace Drupal\facets\Result;
 
+use Drupal\Component\Utility\NestedArray;
 use Drupal\Core\Url;
 use Drupal\facets\FacetInterface;
 
@@ -10,6 +11,13 @@ use Drupal\facets\FacetInterface;
  */
 class Result implements ResultInterface {
 
+  /**
+   * The facet transliterate display value.
+   *
+   * @var string
+   */
+  public $transliterateDisplayValue;
+
   /**
    * The facet related to the result.
    *
@@ -73,6 +81,13 @@ class Result implements ResultInterface {
    */
   protected $children = [];
 
+  /**
+   * Storage for implementation-specific data.
+   *
+   * @var array
+   */
+  protected $storage = [];
+
   /**
    * Constructs a new result value object.
    *
@@ -221,4 +236,34 @@ class Result implements ResultInterface {
     return $this->facet;
   }
 
+  /**
+   * {@inheritdoc}
+   */
+  public function getStorage() {
+    return $this->storage;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function setStorage(array $storage) {
+    $this->storage = $storage;
+    return $this;
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function get($property) {
+    return NestedArray::getValue($this->storage, (array) $property);
+  }
+
+  /**
+   * {@inheritdoc}
+   */
+  public function set($property, $value) {
+    NestedArray::setValue($this->storage, (array) $property, $value, TRUE);
+    return $this;
+  }
+
 }
diff --git a/src/Result/ResultInterface.php b/src/Result/ResultInterface.php
index 3e23b638e0cafa88fa36d443109f164f15043b97..36fbf18374833a90dd423dbbbfb9539f07c4ea41 100644
--- a/src/Result/ResultInterface.php
+++ b/src/Result/ResultInterface.php
@@ -145,4 +145,52 @@ interface ResultInterface {
    */
   public function getChildren();
 
+  /**
+   * Returns the entire set of arbitrary data.
+   *
+   * @return array
+   *   The entire set of arbitrary data storage for this result.
+   */
+  public function getStorage();
+
+  /**
+   * Sets the entire set of arbitrary data.
+   *
+   * @param array $storage
+   *   The entire set of arbitrary data to store for this result.
+   *
+   * @return $this
+   */
+  public function setStorage(array $storage);
+
+  /**
+   * Gets any arbitrary property.
+   *
+   * @param string|array $property
+   *   Properties are often stored as multi-dimensional associative arrays. If
+   *   $property is a string, it will return $storage[$property]. If $property
+   *   is an array, each element of the array will be used as a nested key. If
+   *   $property = ['foo', 'bar'] it will return $storage['foo']['bar'].
+   *
+   * @return mixed
+   *   The property, or the default if the property does not exist.
+   */
+  public function get($property);
+
+  /**
+   * Sets a value to an arbitrary property.
+   *
+   * @param string|array $property
+   *   Properties are often stored as multi-dimensional associative arrays. If
+   *   $property is a string, it will use $storage[$property] = $value. If
+   *   $property is an array, each element of the array will be used as a nested
+   *   key. If $property = ['foo', 'bar'] it will use
+   *   $storage['foo']['bar'] = $value.
+   * @param mixed $value
+   *   The value to set.
+   *
+   * @return $this
+   */
+  public function set($property, $value);
+
 }
diff --git a/tests/src/Unit/Result/ResultTest.php b/tests/src/Unit/Result/ResultTest.php
index b70c8449b1ffa6701a2b56f41bdaed50307ed630..e52c955263a659b8694c86de436ee8a393d30ae3 100644
--- a/tests/src/Unit/Result/ResultTest.php
+++ b/tests/src/Unit/Result/ResultTest.php
@@ -43,6 +43,15 @@ class ResultTest extends UnitTestCase {
     $url = new Url('foo');
     $result->setUrl($url);
     $this->assertSame($url, $result->getUrl());
+
+    $property = ['foo', 'bar'];
+    $value = 'baz';
+    $result->set($property, $value);
+    $this->assertSame($value, $result->get($property));
+
+    $storage = ['foo' => ['bar']];
+    $result->setStorage($storage);
+    $this->assertSame($storage, $result->getStorage());
   }
 
 }