fix: handle cases where hmrData in preview can be null

In case the hmrData is not passed during initial sync, the code will fail with some unexpected exception.
Handle the case and fix unit tests which are successful, but actually throw unhandled error in one of the event handlers.

Author: rosen-vladimirov

lib/controllers/preview-app-controller.ts

@@ -138,7 +138,7 @@ export class PreviewAppController extends EventEmitter implements IPreviewAppCon
 	@performanceLog()
 	private async handlePrepareReadyEvent(data: IPreviewAppLiveSyncData, currentPrepareData: IFilesChangeEventData) {
 		const { hmrData, files, platform } = currentPrepareData;
-		const platformHmrData = _.cloneDeep(hmrData);
+		const platformHmrData = _.cloneDeep(hmrData) || <IPlatformHmrData>{};
 		const connectedDevices = this.$previewDevicesService.getDevicesForPlatform(platform);
 		if (!connectedDevices || !connectedDevices.length) {
 			this.$logger.warn(`Unable to find any connected devices for platform '${platform}'. In order to execute live sync, open your Preview app and optionally re-scan the QR code using the Playground app.`);

test/services/playground/preview-app-livesync-service.ts

@@ -171,7 +171,8 @@ function createTestInjector(options?: {
 		mapFilePath: (filePath: string) => path.join(path.join(platformsDirPath, "app"), path.relative(path.join(projectDirPath, "app"), filePath))
 	});
 	injector.register("previewDevicesService", {
-		getConnectedDevices: () => [deviceMockData]
+		getConnectedDevices: () => [deviceMockData],
+		getDevicesForPlatform: (platform: string): Device[] => [deviceMockData]
 	});
 	injector.register("previewAppFilesService", PreviewAppFilesService);
 	injector.register("previewQrCodeService", {