[lexical-list] Bug Fix: Prevent error when calling formatList when selection is at root

packages/lexical-list/src/__tests__/unit/formatList.test.ts

@@ -0,0 +1,72 @@
+/**
+ * Copyright (c) Meta Platforms, Inc. and affiliates.
+ *
+ * This source code is licensed under the MIT license found in the
+ * LICENSE file in the root directory of this source tree.
+ *
+ */
+
+import {
+  $createTableCellNode,
+  $createTableNode,
+  $createTableRowNode,
+  TableCellNode,
+  TableNode,
+  TableRowNode,
+} from '@lexical/table';
+import {$getRoot} from 'lexical';
+import {initializeUnitTest} from 'lexical/src/__tests__/utils';
+
+import {insertList} from '../../formatList';
+import {$isListNode} from '../../LexicalListNode';
+
+describe('insertList', () => {
+  initializeUnitTest((testEnv) => {
+    test('inserting with empty root selection', async () => {
+      const {editor} = testEnv;
+
+      await editor.update(() => {
+        $getRoot().select();
+      });
+
+      insertList(editor, 'number');
+
+      editor.read(() => {
+        const root = $getRoot();
+
+        expect(root.getChildrenSize()).toBe(1);
+
+        const firstChild = root.getFirstChildOrThrow();
+
+        expect($isListNode(firstChild)).toBe(true);
+      });
+    });
+
+    test('inserting with empty shadow root selection', async () => {
+      const {editor} = testEnv;
+
+      await editor.update(() => {
+        const table = $createTableNode();
+        const row = $createTableRowNode();
+        const cell = $createTableCellNode();
+        $getRoot().append(table.append(row.append(cell)));
+        cell.select();
+      });
+
+      insertList(editor, 'number');
+
+      editor.read(() => {
+        const cell = $getRoot()
+          .getFirstChildOrThrow<TableNode>()
+          .getFirstChildOrThrow<TableRowNode>()
+          .getFirstChildOrThrow<TableCellNode>();
+
+        expect(cell.getChildrenSize()).toBe(1);
+
+        const firstChild = cell.getFirstChildOrThrow();
+
+        expect($isListNode(firstChild)).toBe(true);
+      });
+    });
+  });
+});

packages/lexical-list/src/formatList.ts

@@ -66,7 +66,7 @@ export function insertList(editor: LexicalEditor, listType: ListType): void {
     const selection = $getSelection();
 
     if (selection !== null) {
-      const nodes = selection.getNodes();
+      let nodes = selection.getNodes();
       if ($isRangeSelection(selection)) {
         const anchorAndFocus = selection.getStartEndPoints();
         invariant(
@@ -77,6 +77,17 @@ export function insertList(editor: LexicalEditor, listType: ListType): void {
         const anchorNode = anchor.getNode();
         const anchorNodeParent = anchorNode.getParent();
 
+        if ($isRootOrShadowRoot(anchorNode)) {
+          const firstChild = anchorNode.getFirstChild();
+          if (firstChild) {
+            nodes = firstChild.selectStart().getNodes();
+          } else {
+            const paragraph = $createParagraphNode();
+            anchorNode.append(paragraph);
+            nodes = paragraph.select().getNodes();
+          }
+        }
+
         if ($isSelectingEmptyListItem(anchorNode, nodes)) {
           const list = $createListNode(listType);