Bucket position is not available for all aggs

Author: Spamercz

src/Response/Result/Aggregation/Bucket.php

@@ -15,15 +15,15 @@ class Bucket
 	 */
 	private $docCount;
 	/**
-	 * @var int
+	 * @var int|null
 	 */
 	private $position;
 
 
 	public function __construct(
 		$key
 		, int $docCount
-		, int $position
+		, ?int $position = NULL
 	)
 	{
 		$this->key = $key;
@@ -44,7 +44,7 @@ public function docCount() : int
 	}
 
 
-	public function position() : int
+	public function position() : ?int
 	{
 		return $this->position;
 	}

src/Response/ResultMapper.php

@@ -210,14 +210,14 @@ private function mapAggregation(
 
 
 	private function mapBucket(
-		int $bucketPosition
+		$bucketPosition
 		, array $bucketArray
 	) : \Spameri\ElasticQuery\Response\Result\Aggregation\Bucket
 	{
 		return new \Spameri\ElasticQuery\Response\Result\Aggregation\Bucket(
-			$bucketArray['key'],
+			$bucketArray['key'] ?? $bucketPosition,
 			$bucketArray['doc_count'],
-			$bucketPosition
+			\is_int($bucketPosition) ? $bucketPosition : NULL
 		);
 	}