Merge pull request #4150 from NativeScript/fatme/device-lost-after-timeout

fix(preview-api): raise deviceLost event after timeout of 5 seconds

Author: Fatme

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

@@ -4,6 +4,7 @@ import { DeviceDiscoveryEventNames, DEVICE_LOG_EVENT_NAME } from "../../../../co
 
 export class PreviewDevicesService extends EventEmitter implements IPreviewDevicesService {
 	private connectedDevices: Device[] = [];
+	private deviceLostTimers: IDictionary<NodeJS.Timer> = {};
 
 	constructor(private $previewAppLogProvider: IPreviewAppLogProvider,
 		private $previewAppPluginsService: IPreviewAppPluginsService) {
@@ -23,7 +24,7 @@ export class PreviewDevicesService extends EventEmitter implements IPreviewDevic
 
 		_(this.connectedDevices)
 			.reject(d => _.find(devices, device => d.id === device.id))
-			.each(device => this.raiseDeviceLost(device));
+			.each(device => this.raiseDeviceLostAfterTimeout(device));
 	}
 
 	public getDeviceById(id: string): Device {
@@ -45,6 +46,10 @@ export class PreviewDevicesService extends EventEmitter implements IPreviewDevic
 	}
 
 	private raiseDeviceFound(device: Device) {
+		if (this.deviceLostTimers[device.id]) {
+			clearTimeout(this.deviceLostTimers[device.id]);
+		}
+
 		this.emit(DeviceDiscoveryEventNames.DEVICE_FOUND, device);
 		this.connectedDevices.push(device);
 	}
@@ -53,5 +58,15 @@ export class PreviewDevicesService extends EventEmitter implements IPreviewDevic
 		this.emit(DeviceDiscoveryEventNames.DEVICE_LOST, device);
 		_.remove(this.connectedDevices, d => d.id === device.id);
 	}
+
+	private raiseDeviceLostAfterTimeout(device: Device) {
+		if (!this.deviceLostTimers[device.id]) {
+			const timeoutId = setTimeout(() => {
+				this.raiseDeviceLost(device);
+				clearTimeout(timeoutId);
+			}, 5 * 1000);
+			this.deviceLostTimers[device.id] = timeoutId;
+		}
+	}
 }
 $injector.register("previewDevicesService", PreviewDevicesService);

test/services/preview-devices-service.ts

@@ -4,6 +4,7 @@ import { Device } from "nativescript-preview-sdk";
 import { assert } from "chai";
 import { DeviceDiscoveryEventNames } from "../../lib/common/constants";
 import { LoggerStub, ErrorsStub } from "../stubs";
+import * as sinon from "sinon";
 
 let foundDevices: Device[] = [];
 let lostDevices: Device[] = [];
@@ -38,8 +39,9 @@ function resetDevices() {
 }
 
 describe("PreviewDevicesService", () => {
-	describe("onDevicesPresence", () => {
+	describe("getConnectedDevices", () => {
 		let previewDevicesService: IPreviewDevicesService = null;
+		let clock: sinon.SinonFakeTimers = null;
 		beforeEach(() => {
 			const injector = createTestInjector();
 			previewDevicesService = injector.resolve("previewDevicesService");
@@ -49,11 +51,13 @@ describe("PreviewDevicesService", () => {
 			previewDevicesService.on(DeviceDiscoveryEventNames.DEVICE_LOST, device => {
 				lostDevices.push(device);
 			});
+			clock = sinon.useFakeTimers();
 		});
 
 		afterEach(() => {
 			previewDevicesService.removeAllListeners();
 			resetDevices();
+			clock.restore();
 		});
 
 		it("should add new device", () => {
@@ -101,6 +105,7 @@ describe("PreviewDevicesService", () => {
 			resetDevices();
 
 			previewDevicesService.updateConnectedDevices([]);
+			clock.tick(5000);
 
 			assert.deepEqual(foundDevices, []);
 			assert.deepEqual(lostDevices, [device1]);
@@ -116,10 +121,30 @@ describe("PreviewDevicesService", () => {
 			resetDevices();
 
 			previewDevicesService.updateConnectedDevices([device2]);
+			clock.tick(5000);
 
 			assert.deepEqual(previewDevicesService.getConnectedDevices(), [device2]);
 			assert.deepEqual(foundDevices, [device2]);
 			assert.deepEqual(lostDevices, [device1]);
 		});
+		it("shouldn't emit deviceFound or deviceLost when preview app is restarted on device", () => {
+			const device1 = createDevice("device1");
+
+			previewDevicesService.updateConnectedDevices([device1]);
+
+			assert.deepEqual(previewDevicesService.getConnectedDevices(), [device1]);
+			assert.deepEqual(foundDevices, [device1]);
+			assert.deepEqual(lostDevices, []);
+			resetDevices();
+
+			// preview app is restarted
+			previewDevicesService.updateConnectedDevices([]);
+			clock.tick(500);
+			previewDevicesService.updateConnectedDevices([device1]);
+
+			assert.deepEqual(foundDevices, []);
+			assert.deepEqual(lostDevices, []);
+			assert.deepEqual(previewDevicesService.getConnectedDevices(), [device1]);
+		});
 	});
 });