fix: do not show error from preview initialization when stop is called

lib/commands/preview.ts

@@ -19,17 +19,11 @@ export class PreviewCommand implements ICommand {
 			this.$logger.info(message);
 		});
 
-		await this.$liveSyncService.liveSync([], {
-			syncToPreviewApp: true,
-			projectDir: this.$projectData.projectDir,
-			skipWatcher: !this.$options.watch,
-			watchAllFiles: this.$options.syncAllFiles,
-			clean: this.$options.clean,
+		await this.$liveSyncService.liveSyncToPreviewApp({
 			bundle: !!this.$options.bundle,
-			release: this.$options.release,
-			env: this.$options.env,
-			timeout: this.$options.timeout,
-			useHotModuleReload: this.$options.hmr
+			useHotModuleReload: this.$options.hmr,
+			projectDir: this.$projectData.projectDir,
+			env: this.$options.env
 		});
 
 		await this.$previewQrCodeService.printLiveSyncQrCode({ useHotModuleReload: this.$options.hmr, link: this.$options.link });

lib/definitions/livesync.d.ts

@@ -242,6 +242,13 @@ interface ILiveSyncService {
 	 */
 	liveSync(deviceDescriptors: ILiveSyncDeviceInfo[], liveSyncData: ILiveSyncInfo): Promise<void>;
 
+	/**
+	 * Starts LiveSync operation to Preview app.
+	 * @param {IPreviewAppLiveSyncData} data Describes information about the current operation.
+	 * @returns {Promise<IQrCodeImageData>} Data of the QR code that should be used to start the LiveSync operation.
+	 */
+	liveSyncToPreviewApp(data: IPreviewAppLiveSyncData): Promise<IQrCodeImageData>;
+
 	/**
 	 * Stops LiveSync operation for specified directory.
 	 * @param {string} projectDir The directory for which to stop the operation.

lib/services/livesync/livesync-service.ts

@@ -137,11 +137,13 @@ export class LiveSyncService extends EventEmitter implements IDebugLiveSyncServi
 		return currentDescriptors || [];
 	}
 
-	@cache()
 	private attachToPreviewAppLiveSyncError(): void {
-		this.$previewAppLiveSyncService.on(LiveSyncEvents.previewAppLiveSyncError, liveSyncData => {
-			this.emit(LiveSyncEvents.previewAppLiveSyncError, liveSyncData);
-		});
+		if (!this.$usbLiveSyncService.isInitialized) {
+			this.$previewAppLiveSyncService.on(LiveSyncEvents.previewAppLiveSyncError, liveSyncData => {
+				this.$logger.error(liveSyncData.error);
+				this.emit(LiveSyncEvents.previewAppLiveSyncError, liveSyncData);
+			});
+		}
 	}
 
 	private handleWarnings(liveSyncData: ILiveSyncInfo, projectData: IProjectData) {

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

@@ -43,7 +43,7 @@ export class PreviewAppLiveSyncService extends EventEmitter implements IPreviewA
 					this.deviceInitializationPromise[device.id] = null;
 				}
 			} catch (error) {
-				this.$logger.error(error);
+				this.$logger.trace(`Error while sending files on device ${device && device.id}. Error is`, error);
 				this.emit(PreviewAppLiveSyncEvents.PREVIEW_APP_LIVE_SYNC_ERROR, {
 					error,
 					data,

test/stubs.ts

@@ -661,6 +661,10 @@ export class DebugServiceStub extends EventEmitter implements IDeviceDebugServic
 }
 
 export class LiveSyncServiceStub implements ILiveSyncService {
+	public async liveSyncToPreviewApp(data: IPreviewAppLiveSyncData): Promise<IQrCodeImageData> {
+		return;
+	}
+
 	public async liveSync(deviceDescriptors: ILiveSyncDeviceInfo[], liveSyncData: ILiveSyncInfo): Promise<void> {
 		return;
 	}