diff --git a/README.md b/README.md
index ff0b49f..4439c48 100644
--- a/README.md
+++ b/README.md
@@ -217,10 +217,10 @@ $fileList = $torrent->getFileList();
  *  - TorrentFile::FILETREE_SORT_NORMAL : not sort, also means sort by torrent file parsed order 
  *  - TorrentFile::FILETREE_SORT_STRING : sort by filename ASC ("natural ordering" and "case-insensitively")
  *  - TorrentFile::FILETREE_SORT_FOLDER : sort by filetype (first folder, then file)
- *  - TorrentFile::FILETREE_SORT_NATURAL: sort by both filetype and filename ( same as `TorrentFile::FILETREE_SORT_NAME | TorrentFile::FILETREE_SORT_FOLDER` )
+ *  - TorrentFile::FILETREE_SORT_NATURAL: sort by both filetype and filename ( same as `TorrentFile::FILETREE_SORT_STRING | TorrentFile::FILETREE_SORT_FOLDER` )
  * 
  */
-$fileTree = $torrent->getFileTree(?$sortType = self::FILETREE_SORT_NORMAL);
+$fileTree = $torrent->getFileTree(?$sortType = TorrentFile::FILETREE_SORT_NORMAL);
 
 // 6. Other method
 $torrent->cleanCache();
diff --git a/src/TorrentFile.php b/src/TorrentFile.php
index fc02505..df53bc2 100644
--- a/src/TorrentFile.php
+++ b/src/TorrentFile.php
@@ -40,7 +40,7 @@ class TorrentFile
     public const FILETREE_SORT_NORMAL = 0x00;
     public const FILETREE_SORT_STRING = 0x01;
     public const FILETREE_SORT_FOLDER = 0x10;
-    public const FILETREE_SORT_NATURAL = 0x11;  // same as self::FILETREE_SORT_NAME | self::FILETREE_SORT_FOLDER
+    public const FILETREE_SORT_NATURAL = 0x11;  // same as `self::FILETREE_SORT_STRING | self::FILETREE_SORT_FOLDER`
 
     // store torrent dict
     private $data;
@@ -700,16 +700,16 @@ public function getFileList()
         return $this->parse()['files'];
     }
 
-    private static function sortFileTreeRecursive(array &$fileTree, $sortByName = false, $sortByFolder = false): array
+    private static function sortFileTreeRecursive(array &$fileTree, $sortByString = false, $sortByFolder = false): array
     {
-        if ($sortByName) {
+        if ($sortByString) {
             ksort($fileTree, SORT_NATURAL | SORT_FLAG_CASE);
         }
 
         $isoFile = [];
         foreach ($fileTree as $key => &$item) {
             if (is_array($item)) {
-                $fileTree[$key] = self::sortFileTreeRecursive($item, $sortByName, $sortByFolder);
+                $fileTree[$key] = self::sortFileTreeRecursive($item, $sortByString, $sortByFolder);
             } else if ($sortByFolder) {
                 $isoFile[$key] = $item;
                 unset($fileTree[$key]);
@@ -734,11 +734,11 @@ public function getFileTree($sortType = self::FILETREE_SORT_NORMAL)
     {
         $fileTree = $this->parse()['fileTree'];
 
-        $sortByName = ($sortType & self::FILETREE_SORT_STRING) === self::FILETREE_SORT_STRING;
+        $sortByString = ($sortType & self::FILETREE_SORT_STRING) === self::FILETREE_SORT_STRING;
         $sortByFolder = ($sortType & self::FILETREE_SORT_FOLDER) === self::FILETREE_SORT_FOLDER;
 
-        if ($sortByName || $sortByFolder) {
-            self::sortFileTreeRecursive($fileTree, $sortByName, $sortByFolder);
+        if ($sortByString || $sortByFolder) {
+            self::sortFileTreeRecursive($fileTree, $sortByString, $sortByFolder);
         }
 
         return $fileTree;