Fix type error when continuing list (#3149)

* type error

* list types

Author: juliaroldi

packages/roosterjs-content-model-plugins/lib/autoFormat/list/getListTypeStyle.ts

@@ -131,9 +131,10 @@ const getPreviousListLevel = (
 };
 
 const getPreviousListStyle = (list?: ContentModelListItem) => {
-    if (list?.levels[0].dataset) {
-        return updateListMetadata(list.levels[0])?.orderedStyleType;
+    if (!list || list.levels.length < 1) {
+        return undefined;
     }
+    return updateListMetadata(list.levels[0])?.orderedStyleType;
 };
 
 const bulletListType: Map<string, number> = new Map<string, number>([

packages/roosterjs-content-model-plugins/test/autoFormat/list/getListTypeStyleTest.ts

@@ -1356,4 +1356,59 @@ describe('getListTypeStyle', () => {
             index: 3,
         });
     });
+
+    it('should create a new list', () => {
+        const model: ContentModelDocument = {
+            blockGroupType: 'Document',
+            blocks: [
+                {
+                    formatHolder: {
+                        isSelected: false,
+                        segmentType: 'SelectionMarker',
+                        format: {},
+                    },
+                    levels: [],
+                    blockType: 'BlockGroup',
+                    format: {},
+                    blockGroupType: 'ListItem',
+                    blocks: [
+                        {
+                            segments: [
+                                {
+                                    segmentType: 'Br',
+                                    format: {},
+                                },
+                            ],
+                            segmentFormat: {},
+                            blockType: 'Paragraph',
+                            format: {},
+                        },
+                    ],
+                },
+                {
+                    segments: [
+                        {
+                            text: '1.',
+                            segmentType: 'Text',
+                            format: {},
+                        },
+                        {
+                            isSelected: true,
+                            segmentType: 'SelectionMarker',
+                            format: {},
+                        },
+                    ],
+                    segmentFormat: {},
+                    blockType: 'Paragraph',
+                    format: {},
+                },
+            ],
+            format: {},
+        };
+        runTest(model, {
+            listType: 'OL',
+            styleType: NumberingListType.Decimal,
+            index: undefined,
+        });
+    });
 });