Plugins: Improved note change event handling. Also added tests and improved debugging plugins.

.eslintignore

@@ -86,6 +86,9 @@ packages/app-cli/tests/models_Note.js.map
 packages/app-cli/tests/models_Setting.d.ts
 packages/app-cli/tests/models_Setting.js
 packages/app-cli/tests/models_Setting.js.map
+packages/app-cli/tests/services/plugins/api/JoplinWorkspace.d.ts
+packages/app-cli/tests/services/plugins/api/JoplinWorkspace.js
+packages/app-cli/tests/services/plugins/api/JoplinWorkspace.js.map
 packages/app-cli/tests/services/plugins/sandboxProxy.d.ts
 packages/app-cli/tests/services/plugins/sandboxProxy.js
 packages/app-cli/tests/services/plugins/sandboxProxy.js.map
@@ -1124,6 +1127,9 @@ packages/lib/services/plugins/utils/executeSandboxCall.js.map
 packages/lib/services/plugins/utils/loadContentScripts.d.ts
 packages/lib/services/plugins/utils/loadContentScripts.js
 packages/lib/services/plugins/utils/loadContentScripts.js.map
+packages/lib/services/plugins/utils/makeListener.d.ts
+packages/lib/services/plugins/utils/makeListener.js
+packages/lib/services/plugins/utils/makeListener.js.map
 packages/lib/services/plugins/utils/manifestFromObject.d.ts
 packages/lib/services/plugins/utils/manifestFromObject.js
 packages/lib/services/plugins/utils/manifestFromObject.js.map

.gitignore

@@ -77,6 +77,9 @@ packages/app-cli/tests/models_Note.js.map
 packages/app-cli/tests/models_Setting.d.ts
 packages/app-cli/tests/models_Setting.js
 packages/app-cli/tests/models_Setting.js.map
+packages/app-cli/tests/services/plugins/api/JoplinWorkspace.d.ts
+packages/app-cli/tests/services/plugins/api/JoplinWorkspace.js
+packages/app-cli/tests/services/plugins/api/JoplinWorkspace.js.map
 packages/app-cli/tests/services/plugins/sandboxProxy.d.ts
 packages/app-cli/tests/services/plugins/sandboxProxy.js
 packages/app-cli/tests/services/plugins/sandboxProxy.js.map
@@ -1115,6 +1118,9 @@ packages/lib/services/plugins/utils/executeSandboxCall.js.map
 packages/lib/services/plugins/utils/loadContentScripts.d.ts
 packages/lib/services/plugins/utils/loadContentScripts.js
 packages/lib/services/plugins/utils/loadContentScripts.js.map
+packages/lib/services/plugins/utils/makeListener.d.ts
+packages/lib/services/plugins/utils/makeListener.js
+packages/lib/services/plugins/utils/makeListener.js.map
 packages/lib/services/plugins/utils/manifestFromObject.d.ts
 packages/lib/services/plugins/utils/manifestFromObject.js
 packages/lib/services/plugins/utils/manifestFromObject.js.map

package.json

@@ -37,7 +37,8 @@
     "tsc": "lerna run tsc --stream --parallel",
     "updateIgnored": "gulp updateIgnoredTypeScriptBuild",
     "updatePluginTypes": "./packages/generator-joplin/updateTypes.sh",
-    "watch": "lerna run watch --stream --parallel"
+    "watch": "lerna run watch --stream --parallel",
+    "i": "lerna add --no-bootstrap --scope"
   },
   "husky": {
     "hooks": {

packages/app-cli/app/services/plugins/PluginRunner.ts

@@ -5,6 +5,7 @@ import BasePluginRunner from '@joplin/lib/services/plugins/BasePluginRunner';
 import executeSandboxCall from '@joplin/lib/services/plugins/utils/executeSandboxCall';
 import Global from '@joplin/lib/services/plugins/api/Global';
 import mapEventHandlersToIds, { EventHandlers } from '@joplin/lib/services/plugins/utils/mapEventHandlersToIds';
+import uuid from '@joplin/lib/uuid';
 
 function createConsoleWrapper(pluginId: string) {
 	const wrapper: any = {};
@@ -31,6 +32,7 @@ function createConsoleWrapper(pluginId: string) {
 export default class PluginRunner extends BasePluginRunner {
 
 	private eventHandlers_: EventHandlers = {};
+	private activeSandboxCalls_: any = {};
 
 	constructor() {
 		super();
@@ -45,7 +47,13 @@ export default class PluginRunner extends BasePluginRunner {
 
 	private newSandboxProxy(pluginId: string, sandbox: Global) {
 		const target = async (path: string, args: any[]) => {
-			return executeSandboxCall(pluginId, sandbox, `joplin.${path}`, mapEventHandlersToIds(args, this.eventHandlers_), this.eventHandler);
+			const callId = `${pluginId}::${path}::${uuid.createNano()}`;
+			this.activeSandboxCalls_[callId] = true;
+			const promise = executeSandboxCall(pluginId, sandbox, `joplin.${path}`, mapEventHandlersToIds(args, this.eventHandlers_), this.eventHandler);
+			promise.finally(() => {
+				delete this.activeSandboxCalls_[callId];
+			});
+			return promise;
 		};
 
 		return {
@@ -69,10 +77,25 @@ export default class PluginRunner extends BasePluginRunner {
 				vm.runInContext(plugin.scriptText, vmSandbox);
 			} catch (error) {
 				reject(error);
-				// this.logger().error(`In plugin ${plugin.id}:`, error);
-				// return;
 			}
 		});
 	}
 
+	public async waitForSandboxCalls(): Promise<void> {
+		const startTime = Date.now();
+		return new Promise((resolve: Function, reject: Function) => {
+			const iid = setInterval(() => {
+				if (!Object.keys(this.activeSandboxCalls_).length) {
+					clearInterval(iid);
+					resolve();
+				}
+
+				if (Date.now() - startTime > 4000) {
+					clearInterval(iid);
+					reject(new Error(`Timeout while waiting for sandbox calls to complete: ${JSON.stringify(this.activeSandboxCalls_)}`));
+				}
+			}, 10);
+		});
+	}
+
 }

packages/app-cli/tests/services/plugins/api/JoplinWorkspace.ts

@@ -0,0 +1,52 @@
+import PluginService from '@joplin/lib/services/plugins/PluginService';
+
+const { newPluginService, newPluginScript, setupDatabaseAndSynchronizer, switchClient, afterEachCleanUp } = require('../../../test-utils');
+const Note = require('@joplin/lib/models/Note');
+const Folder = require('@joplin/lib/models/Folder');
+const ItemChange = require('@joplin/lib/models/ItemChange');
+
+describe('JoplinWorkspace', () => {
+
+	beforeEach(async (done) => {
+		await setupDatabaseAndSynchronizer(1);
+		await switchClient(1);
+		done();
+	});
+
+	afterEach(async () => {
+		await afterEachCleanUp();
+	});
+
+	test('should listen to noteChange events', async () => {
+		const service = new newPluginService() as PluginService;
+
+		const pluginScript = newPluginScript(`			
+			joplin.plugins.register({
+				onStart: async function() {
+					await joplin.workspace.onNoteChange(async (event) => {
+						await joplin.data.post(['folders'], null, { title: JSON.stringify(event) });
+					});
+				},
+			});
+		`);
+
+		const note = await Note.save({});
+		await ItemChange.waitForAllSaved();
+
+		const plugin = await service.loadPluginFromJsBundle('', pluginScript);
+		await service.runPlugin(plugin);
+
+		await Note.save({ id: note.id, body: 'testing' });
+		await ItemChange.waitForAllSaved();
+
+		const folder = (await Folder.all())[0];
+
+		const result: any = JSON.parse(folder.title);
+
+		expect(result.id).toBe(note.id);
+		expect(result.event).toBe(ItemChange.TYPE_UPDATE);
+
+		await service.destroy();
+	});
+
+});

packages/app-cli/tests/services_PluginService.ts

@@ -22,9 +22,7 @@ function newPluginService(appVersion: string = '1.4') {
 	service.initialize(
 		appVersion,
 		{
-			joplin: {
-				workspace: {},
-			},
+			joplin: {},
 		},
 		runner,
 		{

packages/app-cli/tests/support/plugins/events/package.json

@@ -20,4 +20,4 @@
     "webpack": "^4.43.0",
     "webpack-cli": "^3.3.11"
   }
-}
+}

packages/app-cli/tests/test-utils.js

@@ -50,6 +50,8 @@ const KeychainServiceDriver = require('@joplin/lib/services/keychain/KeychainSer
 const KeychainServiceDriverDummy = require('@joplin/lib/services/keychain/KeychainServiceDriver.dummy').default;
 const md5 = require('md5');
 const S3 = require('aws-sdk/clients/s3');
+const PluginRunner = require('../app/services/plugins/PluginRunner').default;
+const PluginService = require('@joplin/lib/services/plugins/PluginService').default;
 const { Dirnames } = require('@joplin/lib/services/synchronizer/utils/types');
 const sharp = require('sharp');
 
@@ -677,6 +679,39 @@ async function createTempDir() {
 	return tempDirPath;
 }
 
+function newPluginService(appVersion = '1.4') {
+	const runner = new PluginRunner();
+	const service = new PluginService();
+	service.initialize(
+		appVersion,
+		{
+			joplin: {},
+		},
+		runner,
+		{
+			dispatch: () => {},
+			getState: () => {},
+		}
+	);
+	return service;
+}
+
+function newPluginScript(script) {
+	return `
+		/* joplin-manifest:
+		{
+			"id": "org.joplinapp.plugins.PluginTest",
+			"manifest_version": 1,
+			"app_min_version": "1.4",
+			"name": "JS Bundle test",
+			"version": "1.0.0"
+		}
+		*/
+		
+		${script}
+	`;
+}
+
 // TODO: Update for Jest
 
 // function mockDate(year, month, day, tick) {
@@ -757,4 +792,4 @@ class TestApp extends BaseApplication {
 	}
 }
 
-module.exports = { synchronizerStart, afterEachCleanUp, syncTargetName, setSyncTargetName, syncDir, createTempDir, isNetworkSyncTarget, kvStore, expectThrow, logger, expectNotThrow, resourceService, resourceFetcher, tempFilePath, allSyncTargetItemsEncrypted, msleep, setupDatabase, revisionService, setupDatabaseAndSynchronizer, db, synchronizer, fileApi, sleep, clearDatabase, switchClient, syncTargetId, objectsEqual, checkThrowAsync, checkThrow, encryptionService, loadEncryptionMasterKey, fileContentEqual, decryptionWorker, asyncTest, currentClientId, id, ids, sortedIds, at, createNTestNotes, createNTestFolders, createNTestTags, TestApp };
+module.exports = { newPluginService, newPluginScript, synchronizerStart, afterEachCleanUp, syncTargetName, setSyncTargetName, syncDir, createTempDir, isNetworkSyncTarget, kvStore, expectThrow, logger, expectNotThrow, resourceService, resourceFetcher, tempFilePath, allSyncTargetItemsEncrypted, msleep, setupDatabase, revisionService, setupDatabaseAndSynchronizer, db, synchronizer, fileApi, sleep, clearDatabase, switchClient, syncTargetId, objectsEqual, checkThrowAsync, checkThrow, encryptionService, loadEncryptionMasterKey, fileContentEqual, decryptionWorker, asyncTest, currentClientId, id, ids, sortedIds, at, createNTestNotes, createNTestFolders, createNTestTags, TestApp };

packages/app-desktop/services/plugins/PlatformImplementation.ts

@@ -1,11 +1,5 @@
-// import { EditorCommand } from '@joplin/lib/services/plugins/api/types';
-
 import bridge from '../bridge';
 
-// interface JoplinWorkspace {
-// 	execEditorCommand(command:EditorCommand):Promise<string>
-// }
-
 interface JoplinViewsDialogs {
 	showMessageBox(message: string): Promise<number>;
 }
@@ -15,7 +9,6 @@ interface JoplinViews {
 }
 
 interface Joplin {
-	// workspace: JoplinWorkspace;
 	views: JoplinViews;
 }
 

packages/app-desktop/services/plugins/PluginRunner.ts

@@ -11,6 +11,17 @@ const ipcRenderer = require('electron').ipcRenderer;
 
 const logger = Logger.create('PluginRunner');
 
+// Electron error messages are useless so wrap the renderer call and print
+// additional information when an error occurs.
+function ipcRendererSend(message: string, args: any) {
+	try {
+		return ipcRenderer.send(message, args);
+	} catch (error) {
+		logger.error('Could not send IPC message:', message, ': ', args, error);
+		throw error;
+	}
+}
+
 enum PluginMessageTarget {
 	MainWindow = 'mainWindow',
 	Plugin = 'plugin',
@@ -46,7 +57,7 @@ function mapEventIdsToHandlers(pluginId: string, arg: any) {
 				callbackPromises[callbackId] = { resolve, reject };
 			});
 
-			ipcRenderer.send('pluginMessage', {
+			ipcRendererSend('pluginMessage', {
 				callbackId: callbackId,
 				target: PluginMessageTarget.Plugin,
 				pluginId: pluginId,
@@ -132,7 +143,7 @@ export default class PluginRunner extends BasePluginRunner {
 
 				// Don't log complete HTML code, which can be long, for setHtml calls
 				const debugMappedArgs = fullPath.includes('setHtml') ? '<hidden>' : mappedArgs;
-				logger.debug(`Got message (3): ${fullPath}: ${debugMappedArgs}`);
+				logger.debug(`Got message (3): ${fullPath}`, debugMappedArgs);
 
 				let result: any = null;
 				let error: any = null;
@@ -142,7 +153,7 @@ export default class PluginRunner extends BasePluginRunner {
 					error = e ? e : new Error('Unknown error');
 				}
 
-				ipcRenderer.send('pluginMessage', {
+				ipcRendererSend('pluginMessage', {
 					target: PluginMessageTarget.Plugin,
 					pluginId: plugin.id,
 					pluginCallbackId: message.callbackId,

packages/app-desktop/services/plugins/plugin_index.html

@@ -1,13 +1,5 @@
 <html>
 <head>
 	<script src="./plugin_index.js"></script>
-	<script>
-		// joplin.plugins.register({
-		// 	onStart: async function() {
-		// 		alert('PLUGIN STARTED');
-		// 	},
-		// });	
-	</script>
-</head>
-	
+</head>	
 </html>

packages/app-desktop/services/plugins/plugin_index.js

@@ -3,6 +3,15 @@
 	const sandboxProxy = require('../../node_modules/@joplin/lib/services/plugins/sandboxProxy.js').default;
 	const ipcRenderer = require('electron').ipcRenderer;
 
+	const ipcRendererSend = (message, args) => {
+		try {
+			return ipcRenderer.send(message, args);
+		} catch (error) {
+			console.error('Could not send IPC message:', message, ': ', args, error);
+			throw error;
+		}
+	};
+
 	const urlParams = new URLSearchParams(window.location.search);
 	const pluginId = urlParams.get('pluginId');
 
@@ -42,7 +51,7 @@
 			callbackPromises[callbackId] = { resolve, reject };
 		});
 
-		ipcRenderer.send('pluginMessage', {
+		ipcRendererSend('pluginMessage', {
 			target: 'mainWindow',
 			pluginId: pluginId,
 			callbackId: callbackId,
@@ -71,7 +80,7 @@
 			}
 
 			if (message.callbackId) {
-				ipcRenderer.send('pluginMessage', {
+				ipcRendererSend('pluginMessage', {
 					target: 'mainWindow',
 					pluginId: pluginId,
 					mainWindowCallbackId: message.callbackId,

packages/generator-joplin/.yo-rc.json

@@ -1,9 +0,0 @@
-{
-  "generator-node": {
-    "promptValues": {
-      "authorName": "Laurent Cozic",
-      "authorEmail": "laurent@cozic.net",
-      "authorUrl": ""
-    }
-  }
-}

packages/generator-joplin/LICENSE

@@ -1,6 +1,6 @@
 The MIT License (MIT)
 
-Copyright (c) 2020 Laurent Cozic <laurent@cozic.net>
+Copyright (c) 2020 Laurent Cozic
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

packages/lib/eventManager.ts

@@ -1,6 +1,6 @@
 const events = require('events');
 
-class EventManager {
+export class EventManager {
 
 	private emitter_: any;
 	private appStatePrevious_: any;

packages/lib/jest.config.js

@@ -0,0 +1,13 @@
+module.exports = {
+	testMatch: [
+		'**/*.test.js',
+	],
+
+	testPathIgnorePatterns: [
+		'<rootDir>/node_modules/',
+		'<rootDir>/rnInjectedJs/',
+		'<rootDir>/vendor/',
+	],
+
+	testEnvironment: 'node',
+};

packages/lib/models/ItemChange.js

@@ -1,6 +1,7 @@
 const BaseModel = require('../BaseModel').default;
 const Mutex = require('async-mutex').Mutex;
 const shim = require('../shim').default;
+const eventManager = require('../eventManager').default;
 
 class ItemChange extends BaseModel {
 	static tableName() {
@@ -22,10 +23,25 @@ class ItemChange extends BaseModel {
 		const release = await ItemChange.addChangeMutex_.acquire();
 
 		try {
-			await this.db().transactionExecBatch([{ sql: 'DELETE FROM item_changes WHERE item_id = ?', params: [itemId] }, { sql: 'INSERT INTO item_changes (item_type, item_id, type, source, created_time, before_change_item) VALUES (?, ?, ?, ?, ?, ?)', params: [itemType, itemId, type, changeSource, Date.now(), beforeChangeItemJson] }]);
+			await this.db().transactionExecBatch([
+				{
+					sql: 'DELETE FROM item_changes WHERE item_id = ?',
+					params: [itemId],
+				},
+				{
+					sql: 'INSERT INTO item_changes (item_type, item_id, type, source, created_time, before_change_item) VALUES (?, ?, ?, ?, ?, ?)',
+					params: [itemType, itemId, type, changeSource, Date.now(), beforeChangeItemJson],
+				},
+			]);
 		} finally {
 			release();
 			ItemChange.saveCalls_.pop();
+
+			eventManager.emit('itemChange', {
+				itemType: itemType,
+				itemId: itemId,
+				eventType: type,
+			});
 		}
 	}
 
@@ -62,6 +78,6 @@ ItemChange.TYPE_DELETE = 3;
 
 ItemChange.SOURCE_UNSPECIFIED = 1;
 ItemChange.SOURCE_SYNC = 2;
-ItemChange.SOURCE_DECRYPTION = 2;
+ItemChange.SOURCE_DECRYPTION = 2; // CAREFUL - SAME ID AS SOURCE_SYNC!
 
 module.exports = ItemChange;

packages/lib/package.json

@@ -1,8 +1,8 @@
 {
   "name": "@joplin/lib",
   "version": "1.0.9",
-  "description": "> TODO: description",
-  "author": "Laurent Cozic <laurent@cozic.net>",
+  "description": "Joplin Core library",
+  "author": "Laurent Cozic",
   "homepage": "",
   "license": "ISC",
   "publishConfig": {
@@ -11,9 +11,13 @@
   "scripts": {
     "tsc": "node node_modules/typescript/bin/tsc --project tsconfig.json",
     "watch": "node node_modules/typescript/bin/tsc --watch --project tsconfig.json",
-    "generatePluginTypes": "rm -rf ./plugin_types && node node_modules/typescript/bin/tsc --declaration --declarationDir ./plugin_types --project tsconfig.json"
+    "generatePluginTypes": "rm -rf ./plugin_types && node node_modules/typescript/bin/tsc --declaration --declarationDir ./plugin_types --project tsconfig.json",
+    "test": "jest",
+    "test-ci": "npm run test"
   },
   "devDependencies": {
+    "@types/jest": "^26.0.15",
+    "jest": "^26.6.3",
     "@types/node": "^14.14.6",
     "typescript": "^4.0.5"
   },

packages/lib/services/plugins/BasePluginRunner.ts

@@ -8,4 +8,8 @@ export default abstract class BasePluginRunner extends BaseService {
 		throw new Error(`Not implemented: ${plugin} / ${sandbox}`);
 	}
 
+	public async waitForSandboxCalls(): Promise<void> {
+		throw new Error('Not implemented: waitForSandboxCalls');
+	}
+
 }

packages/lib/services/plugins/PluginService.ts

@@ -385,4 +385,8 @@ export default class PluginService extends BaseService {
 		return newSettings;
 	}
 
+	public async destroy() {
+		await this.runner_.waitForSandboxCalls();
+	}
+
 }

packages/lib/services/plugins/api/Joplin.ts

@@ -37,7 +37,7 @@ export default class Joplin {
 	constructor(implementation: any, plugin: Plugin, store: any) {
 		this.data_ = new JoplinData();
 		this.plugins_ = new JoplinPlugins(plugin);
-		this.workspace_ = new JoplinWorkspace(implementation.workspace, store);
+		this.workspace_ = new JoplinWorkspace(store);
 		this.filters_ = new JoplinFilters();
 		this.commands_ = new JoplinCommands();
 		this.views_ = new JoplinViews(implementation.views, plugin, store);

packages/lib/services/plugins/api/JoplinWorkspace.ts

@@ -1,13 +1,31 @@
+import { ModelType } from '../../../BaseModel';
 import eventManager from '../../../eventManager';
+import makeListener from '../utils/makeListener';
+import { Disposable } from './types';
 
 /**
  * @ignore
  */
 const Note = require('../../../models/Note');
 
+enum ItemChangeEventType {
+	Create = 1,
+	Update = 2,
+	Delete = 3,
+}
+
+interface ItemChangeEvent {
+	id: string;
+	event: ItemChangeEventType;
+}
+
+type ItemChangeHandler = (event: ItemChangeEvent)=> void;
+
 /**
- * The workspace service provides access to all the parts of Joplin that are being worked on - i.e. the currently selected notes or notebooks as well
- * as various related events, such as when a new note is selected, or when the note content changes.
+ * The workspace service provides access to all the parts of Joplin that
+ * are being worked on - i.e. the currently selected notes or notebooks as
+ * well as various related events, such as when a new note is selected, or
+ * when the note content changes.
  *
  * [View the demo plugin](https://github.com/laurent22/joplin/tree/dev/packages/app-cli/tests/support/plugins)
  */
@@ -15,45 +33,68 @@ export default class JoplinWorkspace {
 	// TODO: unregister events when plugin is closed or disabled
 
 	private store: any;
-	// private implementation_:any;
 
-	constructor(_implementation: any, store: any) {
+	constructor(store: any) {
 		this.store = store;
-		// this.implementation_ = implementation;
 	}
 
 	/**
 	 * Called when a new note or notes are selected.
 	 */
-	async onNoteSelectionChange(callback: Function) {
+	public async onNoteSelectionChange(callback: Function): Promise<Disposable> {
 		eventManager.appStateOn('selectedNoteIds', callback);
+
+		return {};
+
+		// return {
+		// 	dispose: () => {
+		// 		eventManager.appStateOff('selectedNoteIds', callback);
+		// 	}
+		// };
+	}
+
+	/**
+	 * Called when the content of a note changes.
+	 * @deprecated Use `onNoteChange()` instead, which is reliably triggered whenever the note content, or any note property changes.
+	 */
+	public async onNoteContentChange(callback: Function) {
+		eventManager.on('noteContentChange', callback);
 	}
 
 	/**
 	 * Called when the content of a note changes.
 	 */
-	async onNoteContentChange(callback: Function) {
-		eventManager.on('noteContentChange', callback);
+	public async onNoteChange(handler: ItemChangeHandler): Promise<Disposable> {
+		const wrapperHandler = (event: any) => {
+			if (event.itemType !== ModelType.Note) return;
+
+			handler({
+				id: event.itemId,
+				event: event.eventType,
+			});
+		};
+
+		return makeListener(eventManager, 'itemChange', wrapperHandler);
 	}
 
 	/**
 	 * Called when an alarm associated with a to-do is triggered.
 	 */
-	async onNoteAlarmTrigger(callback: Function) {
-		eventManager.on('noteAlarmTrigger', callback);
+	public async onNoteAlarmTrigger(callback: Function): Promise<Disposable> {
+		return makeListener(eventManager, 'noteAlarmTrigger', callback);
 	}
 
 	/**
 	 * Called when the synchronisation process has finished.
 	 */
-	async onSyncComplete(callback: Function) {
-		eventManager.on('syncComplete', callback);
+	public async onSyncComplete(callback: Function): Promise<Disposable> {
+		return makeListener(eventManager, 'syncComplete', callback);
 	}
 
 	/**
 	 * Gets the currently selected note
 	 */
-	async selectedNote(): Promise<any> {
+	public async selectedNote(): Promise<any> {
 		const noteIds = this.store.getState().selectedNoteIds;
 		if (noteIds.length !== 1) { return null; }
 		return Note.load(noteIds[0]);
@@ -62,7 +103,7 @@ export default class JoplinWorkspace {
 	/**
 	 * Gets the IDs of the selected notes (can be zero, one, or many). Use the data API to retrieve information about these notes.
 	 */
-	async selectedNoteIds(): Promise<string[]> {
+	public async selectedNoteIds(): Promise<string[]> {
 		return this.store.getState().selectedNoteIds.slice();
 	}
 }

packages/lib/services/plugins/api/types.ts

@@ -189,6 +189,10 @@ export interface Script {
 	onStart?(event: any): Promise<void>;
 }
 
+export interface Disposable {
+	// dispose():void;
+}
+
 // =================================================================
 // Menu types
 // =================================================================

packages/lib/services/plugins/utils/makeListener.ts

@@ -0,0 +1,22 @@
+import { EventManager } from '../../../eventManager';
+import { Disposable } from '../api/types';
+
+export default function(eventManager: EventManager, eventName: string, callback: Function): Disposable {
+	eventManager.on(eventName, callback);
+
+	return {};
+
+	// Note: It is not currently possible to return an object with a dispose() function because function cannot be serialized when sent via IPC. So it would need send callback mechanism as for plugin functions.
+	//
+	// Or it could return a simple string ID, which can then be used to stop listening to the event. eg:
+	//
+	// const listenerId = await joplin.workspace.onNoteChange(() => {});
+	// // ... later:
+	// await joplin.workspace.removeListener(listenerId);
+
+	// return {
+	// 	dispose: () => {
+	// 		eventManager.off(eventName, callback);
+	// 	}
+	// };
+}