fix(data): update DataStore to send correct Control Messages when sta…

…rting (#12861)

.vscode/launch.json

@@ -10,12 +10,12 @@
 			"type": "node",
 			"request": "launch",
 			// The debugger will only run tests for the package specified here:
-			"cwd": "${workspaceFolder}/packages/api-graphql",
+			"cwd": "${workspaceFolder}/packages/datastore",
 			"runtimeArgs": [
 				"--inspect-brk",
 				"${workspaceRoot}/node_modules/.bin/jest",
 				// Optionally specify a single test file to run/debug:
-				"AWSAppSyncRealTimeProvider.test.ts",
+				"connectivityHandling.test.ts",
 				"--runInBand",
 				"--testTimeout",
 				"600000", // 10 min timeout so jest doesn't error while we're stepping through code

packages/datastore/__tests__/conflictResolutionBehavior.test.ts

@@ -1,5 +1,22 @@
 import { warpTime, unwarpTime, pause } from './helpers';
 import { UpdateSequenceHarness } from './helpers/UpdateSequenceHarness';
+import { isNode } from '../src/datastore/utils';
+
+/**
+ * When DataStore starts, DataStore will send Control Messages based on the
+ * environment that tell it what to do. In this testing environment, both
+ * `isNode` and `isBrowser` incorrectly evaluate to `true`. Here we set `isNode`
+ * to `false`, without mocking the other utils.
+ */
+jest.mock('../src/datastore/utils', () => {
+	const originalModule = jest.requireActual('../src/datastore/utils');
+
+	return {
+		__esModule: true,
+		...originalModule,
+		isNode: () => false,
+	};
+});
 
 /**
  * NOTE:

packages/datastore/__tests__/connectivityHandling.test.ts

@@ -10,6 +10,23 @@ import {
 } from './helpers';
 import { Predicates } from '../src/predicates';
 import { syncExpression } from '../src/types';
+import { isNode } from '../src/datastore/utils';
+
+/**
+ * When DataStore starts, DataStore will send Control Messages based on the
+ * environment that tell it what to do. In this testing environment, both
+ * `isNode` and `isBrowser` incorrectly evaluate to `true`. Here we set `isNode`
+ * to `false`, without mocking the other utils.
+ */
+jest.mock('../src/datastore/utils', () => {
+	const originalModule = jest.requireActual('../src/datastore/utils');
+
+	return {
+		__esModule: true,
+		...originalModule,
+		isNode: () => false,
+	};
+});
 
 /**
  * Surfaces errors sooner and outputs them more clearly if/when

packages/datastore/src/datastore/datastore.ts

@@ -72,6 +72,7 @@ import {
 } from '../types';
 // tslint:disable:no-duplicate-imports
 import type { __modelMeta__ } from '../types';
+import { isNode } from './utils';
 
 import {
 	DATASTORE,
@@ -1553,10 +1554,14 @@ class DataStore {
 						.start({ fullSyncInterval: fullSyncIntervalInMilliseconds })
 						.subscribe({
 							next: ({ type, data }) => {
-								// In the Browser, we can begin returning data once subscriptions are in place.
-								const readyType = isBrowser()
-									? ControlMessage.SYNC_ENGINE_STORAGE_SUBSCRIBED
-									: ControlMessage.SYNC_ENGINE_SYNC_QUERIES_READY;
+								/**
+								 * In Node, we need to wait for queries to be synced to prevent returning empty arrays.
+								 * In non-Node environments (the browser or React Native), we can begin returning data
+								 * once subscriptions are in place.
+								 */
+								const readyType = isNode()
+									? ControlMessage.SYNC_ENGINE_SYNC_QUERIES_READY
+									: ControlMessage.SYNC_ENGINE_STORAGE_SUBSCRIBED;
 
 								if (type === readyType) {
 									this.initResolve();

packages/datastore/src/datastore/utils.ts

@@ -0,0 +1,7 @@
+// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+export const isNode = () =>
+	typeof process !== 'undefined' &&
+	process.versions != null &&
+	process.versions.node != null;