Minor fixes

Author: babenkoivan

src/Builders/FilterBuilder.php

@@ -100,25 +100,14 @@ public function whereExists($field)
 
     public function whereNotExists($field)
     {
-        $this->wheres['must_not'][] = [
-            'exists' => [
-                'field' => $field
-            ]
-        ];
+        $this->wheres['must_not'][] = ['exists' => ['field' => $field]];
 
         return $this;
     }
 
     public function whereRegexp($field, $value, $flags = 'ALL')
     {
-        $this->wheres['must'][] = [
-            'regexp' => [
-                $field => [
-                    'value' => $value,
-                    'flags' => $flags
-                ]
-            ]
-        ];
+        $this->wheres['must'][] = ['regexp' => [$field => ['value' => $value, 'flags' => $flags]]];
 
         return $this;
     }

src/ElasticEngine.php

@@ -59,17 +59,21 @@ protected function buildSearchQueryPayload(Builder $builder, $queryPayload, arra
                 continue;
             }
 
-            $queryPayload = array_merge_recursive(
-                $queryPayload,
-                ['filter' => ['bool' => [$clause => $filters]]]
+            if (!array_has($queryPayload, 'filter.bool.'.$clause)) {
+                array_set($queryPayload, 'filter.bool.'.$clause, []);
+            }
+
+            $queryPayload['filter']['bool'][$clause] = array_merge(
+                $queryPayload['filter']['bool'][$clause],
+                $filters
             );
         }
 
         $payload = (new TypePayload($builder->model))
             ->setIfNotEmpty('body.query.bool', $queryPayload)
             ->setIfNotEmpty('body.sort', $builder->orders)
-            ->setIfNotEmpty('body.explain', isset($options['explain']) ? $options['explain'] : null)
-            ->setIfNotEmpty('body.profile', isset($options['profile']) ? $options['profile'] : null);
+            ->setIfNotEmpty('body.explain', $options['explain'] ?? null)
+            ->setIfNotEmpty('body.profile', $options['profile'] ?? null);
 
         if ($size = isset($options['limit']) ? $options['limit'] : $builder->limit) {
             $payload->set('body.size', $size);