Pass externals to sync-preview hook

Author: Fatme

lib/definitions/preview-app-livesync.d.ts

@@ -20,6 +20,7 @@ declare global {
 
 	interface IPreviewAppPluginsService {
 		comparePluginsOnDevice(device: Device): Promise<void>;
+		getExternalPlugins(device: Device): string[];
 	}
 
 	interface IPreviewCommandHelper {

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

@@ -44,6 +44,7 @@ export class PreviewAppLiveSyncService implements IPreviewAppLiveSyncService {
 						platform: device.platform,
 						appFilesUpdaterOptions: data.appFilesUpdaterOptions,
 					},
+					externals: this.$previewAppPluginsService.getExternalPlugins(device),
 					filesToSyncMap,
 				 	startSyncFilesTimeout: startSyncFilesTimeout.bind(this)
 				}

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

@@ -36,6 +36,19 @@ export class PreviewAppPluginsService implements IPreviewAppPluginsService {
 		});
 	}
 
+	public getExternalPlugins(device: Device): any[] {
+		const devicePlugins = this.getDevicePlugins(device);
+		const result = _.keys(devicePlugins)
+			.filter(plugin => plugin.indexOf("nativescript") !== -1)
+			.filter(plugin => !_.includes(["nativescript-angular", "nativescript-vue", "nativescript-intl"], plugin));
+
+		// HACK: We need this in order to work around the following code https://github.com/NativeScript/template-hello-world/blob/master/app/app.js#L7
+		// If we need to remove this, the code above should be changed to: "var application = require("tns-core-modules/application")"
+		result.push(...[ "application"]);
+
+		return result;
+	}
+
 	private getDevicePlugins(device: Device): IStringDictionary {
 		try {
 			return JSON.parse(device.plugins);