Fix bug when trying to delete a model instance that is not persisted

packages/datastore/__tests__/indexeddb.test.ts

@@ -34,7 +34,6 @@ describe('Indexed db storage test', () => {
 		});
 	});
 	test('setup function', async () => {
-		const namespaceResolver = jest.fn();
 		db = await idb.openDB('amplify-datastore', 1);
 
 		const createdObjStores = db.objectStoreNames;
@@ -369,4 +368,19 @@ describe('Indexed db storage test', () => {
 			.getAll(p1.id);
 		expect(refResult).toHaveLength(0);
 	});
+
+	test('delete non existent', async () => {
+		const author = new Author({ name: 'author1' });
+
+		const deleted = await DataStore.delete(author);
+
+		expect(deleted).toStrictEqual(author);
+
+		const fromDB = await db
+			.transaction(`${USER}_Author`, 'readonly')
+			.objectStore(`${USER}_Author`)
+			.get(author.id);
+
+		expect(fromDB).toBeUndefined();
+	});
 });

packages/datastore/src/storage/adapter/indexeddb.ts

@@ -476,6 +476,13 @@ class IndexedDBAdapter implements Adapter {
 
 				const fromDB = await store.get(model.id);
 
+				if (fromDB === undefined) {
+					const msg = 'Model instance not found in storage';
+					logger.warn(msg, { model });
+
+					return [[model], []];
+				}
+
 				const predicates = ModelPredicateCreator.getPredicates(condition);
 				const { predicates: predicateObjs, type } = predicates;