Add a null check in getListAnnounceData (#2964)

* Add a null check in getListAnnounceData

* improve

Author: JiuqingSong

packages/roosterjs-content-model-api/lib/modelApi/list/getListAnnounceData.ts

@@ -24,7 +24,7 @@ export function getListAnnounceData(path: ReadonlyContentModelBlockGroup[]): Ann
         const listItem = path[index] as ContentModelListItem;
         const level = listItem.levels[listItem.levels.length - 1];
 
-        if (level.format.displayForDummyItem) {
+        if (!level || level.format.displayForDummyItem) {
             return null;
         } else if (level.listType == 'OL') {
             const listNumber = getListNumber(path, listItem);

packages/roosterjs-content-model-api/test/modelApi/list/getListAnnounceDataTest.ts

@@ -71,6 +71,18 @@ describe('getListAnnounceData', () => {
         expect(getAutoListStyleTypeSpy).not.toHaveBeenCalled();
     });
 
+    it('path has list item without list levels', () => {
+        const doc = createContentModelDocument();
+        const listItem = createListItem([]);
+
+        doc.blocks.push(listItem);
+
+        const result = getListAnnounceData([listItem, doc]);
+
+        expect(result).toEqual(null);
+        expect(getAutoListStyleTypeSpy).not.toHaveBeenCalled();
+    });
+
     it('path with bullet list', () => {
         const doc = createContentModelDocument();
         const listItem = createListItem([createListLevel('UL')]);