GraphQL\Examples\Blog\Data\DataSource::findStories PHP Method

    public static function findStories($limit, $afterId = null)
    {
        $start = $afterId ? (int) array_search($afterId, array_keys(self::$stories)) + 1 : 0;
        return array_slice(array_values(self::$stories), $start, $limit);
    }

 public function stories($rootValue, $args)
 {
     $args += ['after' => null];
     return DataSource::findStories($args['limit'], $args['after']);
 }