fix: moving a root item after itself does not move the item (#8436)

* fix: moving a root item before itself does not move the item

* Update packages/@react-stately/data/src/useTreeData.ts

---------

Co-authored-by: Robert Snow <[email protected]>
Co-authored-by: Robert Snow <[email protected]>

Author: chirokas

packages/@react-stately/data/src/useTreeData.ts

@@ -502,7 +502,9 @@ function moveItems<T extends object>(
       newMap = nextMap;
     }
     // decrement the index if the child being removed is in the target parent and before the target index
-    if (child.parentKey === toParent?.key
+    // the root node is special, it is null, and will not have a key, however, a parentKey can still point to it
+    if ((child.parentKey === toParent
+       || child.parentKey === toParent?.key)
       && keyArray.includes(child.key)
       && (toParent?.children ? toParent.children.indexOf(child) : items.indexOf(child)) < originalToIndex) {
       toIndex--;

packages/@react-stately/data/test/useTreeData.test.js

@@ -1115,4 +1115,74 @@ describe('useTreeData', function () {
     expect(result.current.items[1].key).toEqual('Emily');
     expect(result.current.items.length).toEqual(2);
   });
+
+  it('should not move the item when moving it before itself', () => {
+    const initialItems = [...initial, {name: 'Emily'}, {name: 'Eli'}];
+  
+    let {result} = renderHook(() => useTreeData({initialItems, getChildren, getKey}));
+    let initialResult = result.current;
+  
+    act(() => {
+      result.current.moveBefore('David', ['David']);
+    });
+    expect(result.current.items).toEqual(initialResult.items);
+  
+    act(() => {
+      result.current.moveBefore('David', ['David', 'Eli']);
+    });
+    expect(result.current.items[0]).toEqual(initialResult.items[0]);
+    expect(result.current.items[1]).toEqual(initialResult.items[2]);
+    expect(result.current.items[2]).toEqual(initialResult.items[1]);
+  
+    act(() => {
+      result.current.moveBefore('John', ['John']);
+    });
+    expect(result.current.items[0]).toEqual(initialResult.items[0]);
+    expect(result.current.items[1]).toEqual(initialResult.items[2]);
+    expect(result.current.items[2]).toEqual(initialResult.items[1]);
+    expect(result.current.items[0].children).toEqual(initialResult.items[0].children);
+  
+    act(() => {
+      result.current.moveBefore('Jane', ['Sam', 'Jane']);
+    });
+    expect(result.current.items[0]).toEqual(initialResult.items[0]);
+    expect(result.current.items[1]).toEqual(initialResult.items[2]);
+    expect(result.current.items[2]).toEqual(initialResult.items[1]);
+    expect(result.current.items[0].children).toEqual(initialResult.items[0].children);
+  });
+  
+  it('should not move the item when moving it after itself', () => {
+    const initialItems = [...initial, {name: 'Emily'}, {name: 'Eli'}];
+  
+    let {result} = renderHook(() => useTreeData({initialItems, getChildren, getKey}));
+    let initialResult = result.current;
+  
+    act(() => {
+      result.current.moveAfter('David', ['David']);
+    });
+    expect(result.current.items).toEqual(initialResult.items);
+  
+    act(() => {
+      result.current.moveAfter('David', ['David', 'Eli']);
+    });
+    expect(result.current.items[0]).toEqual(initialResult.items[0]);
+    expect(result.current.items[1]).toEqual(initialResult.items[2]);
+    expect(result.current.items[2]).toEqual(initialResult.items[1]);
+  
+    act(() => {
+      result.current.moveAfter('John', ['John']);
+    });
+    expect(result.current.items[0]).toEqual(initialResult.items[0]);
+    expect(result.current.items[1]).toEqual(initialResult.items[2]);
+    expect(result.current.items[2]).toEqual(initialResult.items[1]);
+    expect(result.current.items[0].children).toEqual(initialResult.items[0].children);
+  
+    act(() => {
+      result.current.moveAfter('Jane', ['Sam', 'Jane']);
+    });
+    expect(result.current.items[0]).toEqual(initialResult.items[0]);
+    expect(result.current.items[1]).toEqual(initialResult.items[2]);
+    expect(result.current.items[2]).toEqual(initialResult.items[1]);
+    expect(result.current.items[0].children).toEqual(initialResult.items[0].children);
+  });
 });