Fix functional extender #150

example/lib/screens/file_explorer/file_explorer_card.dart

@@ -430,7 +430,7 @@ class _FileExplorerCardState extends State<FileExplorerCard> {
         if (_expanded) ...[
           _buildThumbnail(size: 50),
           _buildDocumentMetadata(),
-          _buildAvailableActions()
+          _buildAvailableActions(),
         ] else
           _buildDocumentSimplifiedTile(),
       ],

example/lib/screens/file_explorer/file_explorer_page.dart

@@ -181,7 +181,7 @@ class _FileExplorerPageState extends State<FileExplorerPage> {
             _buildDocumentList()
           else
             _buildEmptyFolderWarning(),
-        ]
+        ],
       ],
     );
   }

example/lib/screens/granted_uris/granted_uri_card.dart

@@ -69,7 +69,7 @@ class _GrantedUriCardState extends State<GrantedUriCard> {
       ActionButton(
         'Open file picker here',
         onTap: () => openDocumentTree(initialUri: widget.permissionUri.uri),
-      )
+      ),
     ];
   }
 
@@ -193,7 +193,7 @@ class _GrantedUriCardState extends State<GrantedUriCard> {
             didUpdateDocument: (updatedDocumentFile) {
               documentFile = updatedDocumentFile;
             },
-          )
+          ),
       ],
     );
   }

lib/src/common/functional_extender.dart

@@ -25,7 +25,15 @@ extension FunctionalExtender<T> on T? {
   T? takeIf(bool Function(T) f) {
     final T? self = this;
 
-    return self != null && f(self) ? self : null;
+    if (self == null) {
+      return null;
+    }
+
+    if (f(self)) {
+      return self;
+    }
+
+    return null;
   }
 }