Merge pull request #11693 from nanaya/clean-up-graph-json

Clean up user stats json generator

app/helpers.php

@@ -1768,16 +1768,18 @@ function priv_check_user($user, $ability, $object = null)
 }
 
 // Used to generate x,y pairs for fancy-chart.coffee
-function array_to_graph_json(array &$array, $property_to_use)
+function array_to_graph_json(array $array, string $fieldName): array
 {
-    $index = 0;
+    $ret = [];
 
-    return array_map(function ($e) use (&$index, $property_to_use) {
-        return [
-            'x' => $index++,
-            'y' => $e[$property_to_use],
+    foreach ($array as $index => $item) {
+        $ret[] = [
+            'x' => $index,
+            'y' => $item[$fieldName],
         ];
-    }, $array);
+    }
+
+    return $ret;
 }
 
 // Fisher-Yates