Debug on emulator by default when multiple devices/emulators attached

When there are multiple devices/emulators, calling `tns debug android` will fail that multiple devices are attached.
This break VS Code as previous code of CLI has been using emulators by default.
Fix this by using the most recent version (highest API Level) of running emulators, i.e. in case you have three Android emulators with version 5.1, 6.0 and 7.0, the one with 7.0 will be used for debugging.

Author: rosen-vladimirov

Gruntfile.js

@@ -133,7 +133,6 @@ module.exports = function (grunt) {
 	grunt.loadNpmTasks("grunt-contrib-watch");
 	grunt.loadNpmTasks("grunt-shell");
 	grunt.loadNpmTasks("grunt-ts");
-	grunt.loadNpmTasks("grunt-tslint");
 
 	grunt.registerTask("set_package_version", function (version) {
 		var buildVersion = version !== undefined ? version : buildNumber;

lib/commands/debug.ts

@@ -32,8 +32,21 @@
 		await this.$devicesService.detectCurrentlyAttachedDevices();
 
 		// Now let's take data for each device:
-		const devices = this.$devicesService.getDeviceInstances();
-		const deviceDescriptors: ILiveSyncDeviceInfo[] = devices.filter(d => !this.platform || d.deviceInfo.platform === this.platform)
+		let devices = this.$devicesService.getDeviceInstances().filter(d => !this.platform || d.deviceInfo.platform === this.platform);
+
+		if (this.$options.emulator && !this.$options.device) {
+			const emulators = devices.filter(d => d.isEmulator);
+			if (emulators.length > 1) {
+				const sortedEmulators = _.sortBy(emulators, e => e.deviceInfo.version);
+				const selectedEmulator = _.last(sortedEmulators);
+				this.$logger.warn(`Multiple emulators found. Starting debugger on emulator ${selectedEmulator.deviceInfo.identifier}. If you want to debug on specific device/emulator, you can specify it with --device option.`);
+				devices = [selectedEmulator];
+			} else {
+				devices = emulators;
+			}
+		}
+
+		const deviceDescriptors: ILiveSyncDeviceInfo[] = devices
 			.map(d => {
 				const info: ILiveSyncDeviceInfo = {
 					identifier: d.deviceInfo.identifier,
@@ -91,7 +104,9 @@
 		}
 
 		if (this.$devicesService.deviceCount > 1) {
-			this.$errors.failWithoutHelp("Multiple devices found! To debug on specific device please select device with --device option.");
+			this.$options.emulator = true;
+
+			this.$logger.warn("Multiple devices found! Starting debugger on emulator. If you want to debug on specific device please select device with --device option.".yellow.bold);
 		}
 
 		return true;

lib/definitions/debug.d.ts

@@ -83,7 +83,7 @@ interface IDebugDataService {
 	 * @param {IOptions} options The options based on which debugData will be created
 	 * @returns {IDebugData} Data describing the required information for starting debug process.
 	 */
-	createDebugData(projectData: IProjectData, options: IOptions): IDebugData;
+	createDebugData(projectData: IProjectData, options: IDeviceIdentifier): IDebugData;
 }
 
 /**

lib/services/debug-data-service.ts

@@ -1,5 +1,5 @@
 export class DebugDataService implements IDebugDataService {
-	public createDebugData(projectData: IProjectData, options: IOptions): IDebugData {
+	public createDebugData(projectData: IProjectData, options: IDeviceIdentifier): IDebugData {
 		return {
 			applicationIdentifier: projectData.projectId,
 			projectDir: projectData.projectDir,

lib/services/debug-service-base.ts

@@ -14,8 +14,13 @@ export abstract class DebugServiceBase extends EventEmitter implements IPlatform
 	protected getCanExecuteAction(deviceIdentifier: string): (device: Mobile.IDevice) => boolean {
 		return (device: Mobile.IDevice): boolean => {
 			if (deviceIdentifier) {
-				return device.deviceInfo.identifier === deviceIdentifier
-				|| device.deviceInfo.identifier === this.$devicesService.getDeviceByDeviceOption().deviceInfo.identifier;
+				let isSearchedDevice = device.deviceInfo.identifier === deviceIdentifier;
+				if (!isSearchedDevice) {
+					const deviceByDeviceOption = this.$devicesService.getDeviceByDeviceOption();
+					isSearchedDevice = deviceByDeviceOption && device.deviceInfo.identifier === deviceByDeviceOption.deviceInfo.identifier;
+				}
+
+				return isSearchedDevice;
 			} else {
 				return true;
 			}

lib/services/livesync/debug-livesync-service.ts

@@ -46,7 +46,7 @@ export class DebugLiveSyncService extends LiveSyncService implements IDebugLiveS
 			teamId: this.$options.teamId
 		};
 
-		let debugData = this.$debugDataService.createDebugData(this.$projectData, this.$options);
+		let debugData = this.$debugDataService.createDebugData(this.$projectData, { device: liveSyncResultInfo.deviceAppData.device.deviceInfo.identifier });
 		const debugService = this.$debugService.getDebugService(liveSyncResultInfo.deviceAppData.device);
 
 		await this.$platformService.trackProjectType(this.$projectData);