updates for compilation errors

apps/simple/listIndex.ts

@@ -12,4 +12,6 @@ async function main() {
   console.log(response.toString());
 }
 
-main().catch(console.error);
+main().catch((e: Error) => {
+  console.error(e, e.stack);
+});

packages/core/src/BaseIndex.ts

@@ -88,9 +88,16 @@ export interface VectorIndexOptions {
   storageContext?: StorageContext;
 }
 
+interface VectorIndexConstructorProps extends BaseIndexInit<IndexDict> {
+  vectorStore: VectorStore;
+}
+
 export class VectorStoreIndex extends BaseIndex<IndexDict> {
-  private constructor(init: BaseIndexInit<IndexDict>) {
+  vectorStore: VectorStore;
+
+  private constructor(init: VectorIndexConstructorProps) {
     super(init);
+    this.vectorStore = init.vectorStore;
   }
 
   static async init(options: VectorIndexOptions): Promise<VectorStoreIndex> {