refactor: consolidate all events in Events.js (#3772)

This will allow us to break all dependency cycles that were forcing
us to put many things in a single file (e.g. ExecutionContext and
ElementHandle).

lib/Browser.js

@@ -18,7 +18,7 @@ const { helper, assert } = require('./helper');
 const {Target} = require('./Target');
 const EventEmitter = require('events');
 const {TaskQueue} = require('./TaskQueue');
-const {Connection} = require('./Connection');
+const {Events} = require('./Events');
 
 class Browser extends EventEmitter {
   /**
@@ -46,7 +46,7 @@ class Browser extends EventEmitter {
 
     /** @type {Map<string, Target>} */
     this._targets = new Map();
-    this._connection.on(Connection.Events.Disconnected, () => this.emit(Browser.Events.Disconnected));
+    this._connection.on(Events.Connection.Disconnected, () => this.emit(Events.Browser.Disconnected));
     this._connection.on('Target.targetCreated', this._targetCreated.bind(this));
     this._connection.on('Target.targetDestroyed', this._targetDestroyed.bind(this));
     this._connection.on('Target.targetInfoChanged', this._targetInfoChanged.bind(this));
@@ -118,8 +118,8 @@ class Browser extends EventEmitter {
     this._targets.set(event.targetInfo.targetId, target);
 
     if (await target._initializedPromise) {
-      this.emit(Browser.Events.TargetCreated, target);
-      context.emit(BrowserContext.Events.TargetCreated, target);
+      this.emit(Events.Browser.TargetCreated, target);
+      context.emit(Events.BrowserContext.TargetCreated, target);
     }
   }
 
@@ -132,8 +132,8 @@ class Browser extends EventEmitter {
     this._targets.delete(event.targetId);
     target._closedCallback();
     if (await target._initializedPromise) {
-      this.emit(Browser.Events.TargetDestroyed, target);
-      target.browserContext().emit(BrowserContext.Events.TargetDestroyed, target);
+      this.emit(Events.Browser.TargetDestroyed, target);
+      target.browserContext().emit(Events.BrowserContext.TargetDestroyed, target);
     }
   }
 
@@ -147,8 +147,8 @@ class Browser extends EventEmitter {
     const wasInitialized = target._isInitialized;
     target._targetInfoChanged(event.targetInfo);
     if (wasInitialized && previousURL !== target.url()) {
-      this.emit(Browser.Events.TargetChanged, target);
-      target.browserContext().emit(BrowserContext.Events.TargetChanged, target);
+      this.emit(Events.Browser.TargetChanged, target);
+      target.browserContext().emit(Events.BrowserContext.TargetChanged, target);
     }
   }
 
@@ -206,15 +206,15 @@ class Browser extends EventEmitter {
       return existingTarget;
     let resolve;
     const targetPromise = new Promise(x => resolve = x);
-    this.on(Browser.Events.TargetCreated, check);
-    this.on(Browser.Events.TargetChanged, check);
+    this.on(Events.Browser.TargetCreated, check);
+    this.on(Events.Browser.TargetChanged, check);
     try {
       if (!timeout)
         return await targetPromise;
       return await helper.waitWithTimeout(targetPromise, 'target', timeout);
     } finally {
-      this.removeListener(Browser.Events.TargetCreated, check);
-      this.removeListener(Browser.Events.TargetChanged, check);
+      this.removeListener(Events.Browser.TargetCreated, check);
+      this.removeListener(Events.Browser.TargetChanged, check);
     }
 
     /**
@@ -268,14 +268,6 @@ class Browser extends EventEmitter {
   }
 }
 
-/** @enum {string} */
-Browser.Events = {
-  TargetCreated: 'targetcreated',
-  TargetDestroyed: 'targetdestroyed',
-  TargetChanged: 'targetchanged',
-  Disconnected: 'disconnected'
-};
-
 class BrowserContext extends EventEmitter {
   /**
    * @param {!Puppeteer.Connection} connection
@@ -381,13 +373,6 @@ class BrowserContext extends EventEmitter {
   }
 }
 
-/** @enum {string} */
-BrowserContext.Events = {
-  TargetCreated: 'targetcreated',
-  TargetDestroyed: 'targetdestroyed',
-  TargetChanged: 'targetchanged',
-};
-
 helper.tracePublicAPI(BrowserContext);
 helper.tracePublicAPI(Browser);
 

lib/Connection.js

@@ -14,6 +14,7 @@
  * limitations under the License.
  */
 const {helper, assert} = require('./helper');
+const {Events} = require('./Events');
 const debugProtocol = require('debug')('puppeteer:protocol');
 const debugSession = require('debug')('puppeteer:session');
 const EventEmitter = require('events');
@@ -120,7 +121,7 @@ class Connection extends EventEmitter {
     for (const session of this._sessions.values())
       session._onClosed();
     this._sessions.clear();
-    this.emit(Connection.Events.Disconnected);
+    this.emit(Events.Connection.Disconnected);
   }
 
   dispose() {
@@ -140,10 +141,6 @@ class Connection extends EventEmitter {
   }
 }
 
-Connection.Events = {
-  Disconnected: Symbol('Connection.Events.Disconnected'),
-};
-
 class CDPSession extends EventEmitter {
   /**
    * @param {!Connection|!CDPSession} connection
@@ -228,7 +225,7 @@ class CDPSession extends EventEmitter {
       callback.reject(rewriteError(callback.error, `Protocol error (${callback.method}): Target closed.`));
     this._callbacks.clear();
     this._connection = null;
-    this.emit(CDPSession.Events.Disconnected);
+    this.emit(Events.CDPSession.Disconnected);
   }
 
   /**
@@ -242,10 +239,6 @@ class CDPSession extends EventEmitter {
   }
 }
 
-CDPSession.Events = {
-  Disconnected: Symbol('CDPSession.Events.Disconnected'),
-};
-
 helper.tracePublicAPI(CDPSession);
 
 /**

lib/Events.js

@@ -0,0 +1,80 @@
+/**
+ * Copyright 2019 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+const Events = {
+  Page: {
+    Close: 'close',
+    Console: 'console',
+    Dialog: 'dialog',
+    DOMContentLoaded: 'domcontentloaded',
+    Error: 'error',
+    // Can't use just 'error' due to node.js special treatment of error events.
+    // @see https://nodejs.org/api/events.html#events_error_events
+    PageError: 'pageerror',
+    Request: 'request',
+    Response: 'response',
+    RequestFailed: 'requestfailed',
+    RequestFinished: 'requestfinished',
+    FrameAttached: 'frameattached',
+    FrameDetached: 'framedetached',
+    FrameNavigated: 'framenavigated',
+    Load: 'load',
+    Metrics: 'metrics',
+    Popup: 'popup',
+    WorkerCreated: 'workercreated',
+    WorkerDestroyed: 'workerdestroyed',
+  },
+
+  Browser: {
+    TargetCreated: 'targetcreated',
+    TargetDestroyed: 'targetdestroyed',
+    TargetChanged: 'targetchanged',
+    Disconnected: 'disconnected'
+  },
+
+  BrowserContext: {
+    TargetCreated: 'targetcreated',
+    TargetDestroyed: 'targetdestroyed',
+    TargetChanged: 'targetchanged',
+  },
+
+  NetworkManager: {
+    Request: Symbol('Events.NetworkManager.Request'),
+    Response: Symbol('Events.NetworkManager.Response'),
+    RequestFailed: Symbol('Events.NetworkManager.RequestFailed'),
+    RequestFinished: Symbol('Events.NetworkManager.RequestFinished'),
+  },
+
+  FrameManager: {
+    FrameAttached: Symbol('Events.FrameManager.FrameAttached'),
+    FrameNavigated: Symbol('Events.FrameManager.FrameNavigated'),
+    FrameDetached: Symbol('Events.FrameManager.FrameDetached'),
+    LifecycleEvent: Symbol('Events.FrameManager.LifecycleEvent'),
+    FrameNavigatedWithinDocument: Symbol('Events.FrameManager.FrameNavigatedWithinDocument'),
+    ExecutionContextCreated: Symbol('Events.FrameManager.ExecutionContextCreated'),
+    ExecutionContextDestroyed: Symbol('Events.FrameManager.ExecutionContextDestroyed'),
+  },
+
+  Connection: {
+    Disconnected: Symbol('Events.Connection.Disconnected'),
+  },
+
+  CDPSession: {
+    Disconnected: Symbol('Events.CDPSession.Disconnected'),
+  },
+};
+
+module.exports = { Events };

lib/FrameManager.js

@@ -17,10 +17,9 @@
 const fs = require('fs');
 const EventEmitter = require('events');
 const {helper, assert} = require('./helper');
+const {Events} = require('./Events');
 const {ExecutionContext} = require('./ExecutionContext');
 const {TimeoutError} = require('./Errors');
-const {NetworkManager} = require('./NetworkManager');
-const {CDPSession} = require('./Connection');
 
 const readFileAsync = helper.promisify(fs.readFile);
 
@@ -142,7 +141,7 @@ class FrameManager extends EventEmitter {
     if (!frame)
       return;
     frame._onLifecycleEvent(event.loaderId, event.name);
-    this.emit(FrameManager.Events.LifecycleEvent, frame);
+    this.emit(Events.FrameManager.LifecycleEvent, frame);
   }
 
   /**
@@ -153,7 +152,7 @@ class FrameManager extends EventEmitter {
     if (!frame)
       return;
     frame._onLoadingStopped();
-    this.emit(FrameManager.Events.LifecycleEvent, frame);
+    this.emit(Events.FrameManager.LifecycleEvent, frame);
   }
 
   /**
@@ -210,7 +209,7 @@ class FrameManager extends EventEmitter {
     const parentFrame = this._frames.get(parentFrameId);
     const frame = new Frame(this, this._client, parentFrame, frameId);
     this._frames.set(frame._id, frame);
-    this.emit(FrameManager.Events.FrameAttached, frame);
+    this.emit(Events.FrameManager.FrameAttached, frame);
   }
 
   /**
@@ -244,7 +243,7 @@ class FrameManager extends EventEmitter {
     // Update frame payload.
     frame._navigated(framePayload);
 
-    this.emit(FrameManager.Events.FrameNavigated, frame);
+    this.emit(Events.FrameManager.FrameNavigated, frame);
   }
 
   /**
@@ -256,8 +255,8 @@ class FrameManager extends EventEmitter {
     if (!frame)
       return;
     frame._navigatedWithinDocument(url);
-    this.emit(FrameManager.Events.FrameNavigatedWithinDocument, frame);
-    this.emit(FrameManager.Events.FrameNavigated, frame);
+    this.emit(Events.FrameManager.FrameNavigatedWithinDocument, frame);
+    this.emit(Events.FrameManager.FrameNavigated, frame);
   }
 
   /**
@@ -317,21 +316,10 @@ class FrameManager extends EventEmitter {
       this._removeFramesRecursively(child);
     frame._detach();
     this._frames.delete(frame._id);
-    this.emit(FrameManager.Events.FrameDetached, frame);
+    this.emit(Events.FrameManager.FrameDetached, frame);
   }
 }
 
-/** @enum {string} */
-FrameManager.Events = {
-  FrameAttached: 'frameattached',
-  FrameNavigated: 'framenavigated',
-  FrameDetached: 'framedetached',
-  LifecycleEvent: 'lifecycleevent',
-  FrameNavigatedWithinDocument: 'framenavigatedwithindocument',
-  ExecutionContextCreated: 'executioncontextcreated',
-  ExecutionContextDestroyed: 'executioncontextdestroyed',
-};
-
 /**
  * @unrestricted
  */
@@ -1180,11 +1168,11 @@ class LifecycleWatcher {
     /** @type {?Puppeteer.Request} */
     this._navigationRequest = null;
     this._eventListeners = [
-      helper.addEventListener(frameManager._client, CDPSession.Events.Disconnected, () => this._terminate(new Error('Navigation failed because browser has disconnected!'))),
-      helper.addEventListener(this._frameManager, FrameManager.Events.LifecycleEvent, this._checkLifecycleComplete.bind(this)),
-      helper.addEventListener(this._frameManager, FrameManager.Events.FrameNavigatedWithinDocument, this._navigatedWithinDocument.bind(this)),
-      helper.addEventListener(this._frameManager, FrameManager.Events.FrameDetached, this._onFrameDetached.bind(this)),
-      helper.addEventListener(this._networkManager, NetworkManager.Events.Request, this._onRequest.bind(this)),
+      helper.addEventListener(frameManager._client, Events.CDPSession.Disconnected, () => this._terminate(new Error('Navigation failed because browser has disconnected!'))),
+      helper.addEventListener(this._frameManager, Events.FrameManager.LifecycleEvent, this._checkLifecycleComplete.bind(this)),
+      helper.addEventListener(this._frameManager, Events.FrameManager.FrameNavigatedWithinDocument, this._navigatedWithinDocument.bind(this)),
+      helper.addEventListener(this._frameManager, Events.FrameManager.FrameDetached, this._onFrameDetached.bind(this)),
+      helper.addEventListener(this._networkManager, Events.NetworkManager.Request, this._onRequest.bind(this)),
     ];
 
     this._sameDocumentNavigationPromise = new Promise(fulfill => {

lib/NetworkManager.js

@@ -15,6 +15,7 @@
  */
 const EventEmitter = require('events');
 const {helper, assert, debugError} = require('./helper');
+const {Events} = require('./Events');
 const Multimap = require('./Multimap');
 
 class NetworkManager extends EventEmitter {
@@ -206,7 +207,7 @@ class NetworkManager extends EventEmitter {
     const frame = event.frameId && this._frameManager ? this._frameManager.frame(event.frameId) : null;
     const request = new Request(this._client, frame, interceptionId, this._userRequestInterceptionEnabled, event, redirectChain);
     this._requestIdToRequest.set(event.requestId, request);
-    this.emit(NetworkManager.Events.Request, request);
+    this.emit(Events.NetworkManager.Request, request);
   }
 
 
@@ -230,8 +231,8 @@ class NetworkManager extends EventEmitter {
     response._bodyLoadedPromiseFulfill.call(null, new Error('Response body is unavailable for redirect responses'));
     this._requestIdToRequest.delete(request._requestId);
     this._attemptedAuthentications.delete(request._interceptionId);
-    this.emit(NetworkManager.Events.Response, response);
-    this.emit(NetworkManager.Events.RequestFinished, request);
+    this.emit(Events.NetworkManager.Response, response);
+    this.emit(Events.NetworkManager.RequestFinished, request);
   }
 
   /**
@@ -244,7 +245,7 @@ class NetworkManager extends EventEmitter {
       return;
     const response = new Response(this._client, request, event.response);
     request._response = response;
-    this.emit(NetworkManager.Events.Response, response);
+    this.emit(Events.NetworkManager.Response, response);
   }
 
   /**
@@ -263,7 +264,7 @@ class NetworkManager extends EventEmitter {
       request.response()._bodyLoadedPromiseFulfill.call(null);
     this._requestIdToRequest.delete(request._requestId);
     this._attemptedAuthentications.delete(request._interceptionId);
-    this.emit(NetworkManager.Events.RequestFinished, request);
+    this.emit(Events.NetworkManager.RequestFinished, request);
   }
 
   /**
@@ -281,7 +282,7 @@ class NetworkManager extends EventEmitter {
       response._bodyLoadedPromiseFulfill.call(null);
     this._requestIdToRequest.delete(request._requestId);
     this._attemptedAuthentications.delete(request._interceptionId);
-    this.emit(NetworkManager.Events.RequestFailed, request);
+    this.emit(Events.NetworkManager.RequestFailed, request);
   }
 }
 
@@ -732,13 +733,6 @@ class SecurityDetails {
   }
 }
 
-NetworkManager.Events = {
-  Request: 'request',
-  Response: 'response',
-  RequestFailed: 'requestfailed',
-  RequestFinished: 'requestfinished',
-};
-
 const statusTexts = {
   '100': 'Continue',
   '101': 'Switching Protocols',

lib/Page.js

@@ -17,6 +17,7 @@
 const fs = require('fs');
 const EventEmitter = require('events');
 const mime = require('mime');
+const {Events} = require('./Events');
 const {NetworkManager} = require('./NetworkManager');
 const {Dialog} = require('./Dialog');
 const {EmulationManager} = require('./EmulationManager');
@@ -108,28 +109,28 @@ class Page extends EventEmitter {
       const session = client._createSession(event.targetInfo.type, event.sessionId);
       const worker = new Worker(session, event.targetInfo.url, this._addConsoleMessage.bind(this), this._handleException.bind(this));
       this._workers.set(event.sessionId, worker);
-      this.emit(Page.Events.WorkerCreated, worker);
+      this.emit(Events.Page.WorkerCreated, worker);
 
     });
     client.on('Target.detachedFromTarget', event => {
       const worker = this._workers.get(event.sessionId);
       if (!worker)
         return;
-      this.emit(Page.Events.WorkerDestroyed, worker);
+      this.emit(Events.Page.WorkerDestroyed, worker);
       this._workers.delete(event.sessionId);
     });
 
-    this._frameManager.on(FrameManager.Events.FrameAttached, event => this.emit(Page.Events.FrameAttached, event));
-    this._frameManager.on(FrameManager.Events.FrameDetached, event => this.emit(Page.Events.FrameDetached, event));
-    this._frameManager.on(FrameManager.Events.FrameNavigated, event => this.emit(Page.Events.FrameNavigated, event));
+    this._frameManager.on(Events.FrameManager.FrameAttached, event => this.emit(Events.Page.FrameAttached, event));
+    this._frameManager.on(Events.FrameManager.FrameDetached, event => this.emit(Events.Page.FrameDetached, event));
+    this._frameManager.on(Events.FrameManager.FrameNavigated, event => this.emit(Events.Page.FrameNavigated, event));
 
-    this._networkManager.on(NetworkManager.Events.Request, event => this.emit(Page.Events.Request, event));
-    this._networkManager.on(NetworkManager.Events.Response, event => this.emit(Page.Events.Response, event));
-    this._networkManager.on(NetworkManager.Events.RequestFailed, event => this.emit(Page.Events.RequestFailed, event));
-    this._networkManager.on(NetworkManager.Events.RequestFinished, event => this.emit(Page.Events.RequestFinished, event));
+    this._networkManager.on(Events.NetworkManager.Request, event => this.emit(Events.Page.Request, event));
+    this._networkManager.on(Events.NetworkManager.Response, event => this.emit(Events.Page.Response, event));
+    this._networkManager.on(Events.NetworkManager.RequestFailed, event => this.emit(Events.Page.RequestFailed, event));
+    this._networkManager.on(Events.NetworkManager.RequestFinished, event => this.emit(Events.Page.RequestFinished, event));
 
-    client.on('Page.domContentEventFired', event => this.emit(Page.Events.DOMContentLoaded));
-    client.on('Page.loadEventFired', event => this.emit(Page.Events.Load));
+    client.on('Page.domContentEventFired', event => this.emit(Events.Page.DOMContentLoaded));
+    client.on('Page.loadEventFired', event => this.emit(Events.Page.Load));
     client.on('Runtime.consoleAPICalled', event => this._onConsoleAPI(event));
     client.on('Runtime.bindingCalled', event => this._onBindingCalled(event));
     client.on('Page.javascriptDialogOpening', event => this._onDialog(event));
@@ -139,7 +140,7 @@ class Page extends EventEmitter {
     client.on('Performance.metrics', event => this._emitMetrics(event));
     client.on('Log.entryAdded', event => this._onLogEntryAdded(event));
     this._target._isClosedPromise.then(() => {
-      this.emit(Page.Events.Close);
+      this.emit(Events.Page.Close);
       this._closed = true;
     });
   }
@@ -191,7 +192,7 @@ class Page extends EventEmitter {
     if (args)
       args.map(arg => helper.releaseObject(this._client, arg));
     if (source !== 'worker')
-      this.emit(Page.Events.Console, new ConsoleMessage(level, text, [], {url, lineNumber}));
+      this.emit(Events.Page.Console, new ConsoleMessage(level, text, [], {url, lineNumber}));
   }
 
   /**
@@ -475,7 +476,7 @@ class Page extends EventEmitter {
    * @param {!Protocol.Performance.metricsPayload} event
    */
   _emitMetrics(event) {
-    this.emit(Page.Events.Metrics, {
+    this.emit(Events.Page.Metrics, {
       title: event.title,
       metrics: this._buildMetricsObject(event.metrics)
     });
@@ -501,7 +502,7 @@ class Page extends EventEmitter {
     const message = helper.getExceptionMessage(exceptionDetails);
     const err = new Error(message);
     err.stack = ''; // Don't report clientside error with a node stack attached
-    this.emit(Page.Events.PageError, err);
+    this.emit(Events.Page.PageError, err);
   }
 
   /**
@@ -570,7 +571,7 @@ class Page extends EventEmitter {
    * @param {Protocol.Runtime.StackTrace=} stackTrace
    */
   _addConsoleMessage(type, args, stackTrace) {
-    if (!this.listenerCount(Page.Events.Console)) {
+    if (!this.listenerCount(Events.Page.Console)) {
       args.forEach(arg => arg.dispose());
       return;
     }
@@ -588,7 +589,7 @@ class Page extends EventEmitter {
       columnNumber: stackTrace.callFrames[0].columnNumber,
     } : {};
     const message = new ConsoleMessage(type, textTokens.join(' '), args, location);
-    this.emit(Page.Events.Console, message);
+    this.emit(Events.Page.Console, message);
   }
 
   _onDialog(event) {
@@ -603,7 +604,7 @@ class Page extends EventEmitter {
       dialogType = Dialog.Type.BeforeUnload;
     assert(dialogType, 'Unknown javascript dialog type: ' + event.type);
     const dialog = new Dialog(this._client, dialogType, event.message, event.defaultPrompt);
-    this.emit(Page.Events.Dialog, dialog);
+    this.emit(Events.Page.Dialog, dialog);
   }
 
   /**
@@ -666,7 +667,7 @@ class Page extends EventEmitter {
     const {
       timeout = 30000
     } = options;
-    return helper.waitForEvent(this._networkManager, NetworkManager.Events.Request, request => {
+    return helper.waitForEvent(this._networkManager, Events.NetworkManager.Request, request => {
       if (helper.isString(urlOrPredicate))
         return (urlOrPredicate === request.url());
       if (typeof urlOrPredicate === 'function')
@@ -684,7 +685,7 @@ class Page extends EventEmitter {
     const {
       timeout = 30000
     } = options;
-    return helper.waitForEvent(this._networkManager, NetworkManager.Events.Response, response => {
+    return helper.waitForEvent(this._networkManager, Events.NetworkManager.Response, response => {
       if (helper.isString(urlOrPredicate))
         return (urlOrPredicate === response.url());
       if (typeof urlOrPredicate === 'function')
@@ -1182,30 +1183,6 @@ function convertPrintParameterToInches(parameter) {
   return pixels / 96;
 }
 
-Page.Events = {
-  Close: 'close',
-  Console: 'console',
-  Dialog: 'dialog',
-  DOMContentLoaded: 'domcontentloaded',
-  Error: 'error',
-  // Can't use just 'error' due to node.js special treatment of error events.
-  // @see https://nodejs.org/api/events.html#events_error_events
-  PageError: 'pageerror',
-  Request: 'request',
-  Response: 'response',
-  RequestFailed: 'requestfailed',
-  RequestFinished: 'requestfinished',
-  FrameAttached: 'frameattached',
-  FrameDetached: 'framedetached',
-  FrameNavigated: 'framenavigated',
-  Load: 'load',
-  Metrics: 'metrics',
-  Popup: 'popup',
-  WorkerCreated: 'workercreated',
-  WorkerDestroyed: 'workerdestroyed',
-};
-
-
 /**
  * @typedef {Object} Network.Cookie
  * @property {string} name

lib/Target.js

@@ -1,3 +1,4 @@
+const {Events} = require('./Events');
 const {Page} = require('./Page');
 const {helper} = require('./helper');
 
@@ -27,10 +28,10 @@ class Target {
       if (!opener || !opener._pagePromise || this.type() !== 'page')
         return true;
       const openerPage = await opener._pagePromise;
-      if (!openerPage.listenerCount(Page.Events.Popup))
+      if (!openerPage.listenerCount(Events.Page.Popup))
         return true;
       const popupPage = await this.page();
-      openerPage.emit(Page.Events.Popup, popupPage);
+      openerPage.emit(Events.Page.Popup, popupPage);
       return true;
     });
     this._isClosedPromise = new Promise(fulfill => this._closedCallback = fulfill);

lib/helper.js

@@ -220,7 +220,7 @@ class Helper {
 
   /**
    * @param {!NodeJS.EventEmitter} emitter
-   * @param {string} eventName
+   * @param {(string|symbol)} eventName
    * @param {function} predicate
    * @return {!Promise}
    */

utils/doclint/check_public_api/JSBuilder.js

@@ -7,6 +7,15 @@ module.exports = checkSources;
  * @param {!Array<!import('../Source')>} sources
  */
 function checkSources(sources) {
+  // special treatment for Events.js
+  const classEvents = new Map();
+  const eventsSource = sources.find(source => source.name() === 'Events.js');
+  if (eventsSource) {
+    const {Events} = require(eventsSource.filePath());
+    for (const [className, events] of Object.entries(Events))
+      classEvents.set(className, Array.from(Object.values(events)).filter(e => typeof e === 'string').map(e => Documentation.Member.createEvent(e)));
+  }
+
   const excludeClasses = new Set([]);
   const program = ts.createProgram({
     options: {
@@ -24,6 +33,7 @@ function checkSources(sources) {
   sourceFiles.filter(x => !x.fileName.includes('node_modules')).map(x => visit(x));
   const errors = [];
   const documentation = new Documentation(recreateClassesWithInheritance(classes, inheritance));
+
   return {errors, documentation};
 
   /**
@@ -158,17 +168,7 @@ function checkSources(sources) {
    */
   function serializeClass(className, symbol, node) {
     /** @type {!Array<!Documentation.Member>} */
-    const members = [];
-
-    const type = checker.getTypeOfSymbolAtLocation(symbol, node);
-    const events = type.getProperty('Events');
-    if (events) {
-      const eventType = checker.getTypeAtLocation(events.valueDeclaration);
-      for (const property of eventType.getProperties()) {
-        if (property.valueDeclaration.initializer.text)
-          members.push(Documentation.Member.createEvent(property.valueDeclaration.initializer.text));
-      }
-    }
+    const members = classEvents.get(className) || [];
 
     for (const [name, member] of symbol.members || []) {
       if (name.startsWith('_'))

utils/doclint/check_public_api/test/check-sorting/Events.js

@@ -0,0 +1,8 @@
+const Events = {
+  Foo: {
+    a: 'a',
+    b: 'b',
+    c: 'c',
+  },
+};
+module.exports = {Events};

utils/doclint/check_public_api/test/check-sorting/foo.js

@@ -10,8 +10,3 @@ class Foo {
   ccc() {}
 }
 
-Foo.Events = {
-  a: 'a',
-  b: 'b',
-  c: 'c'
-}

utils/doclint/check_public_api/test/diff-events/Events.js

@@ -0,0 +1,8 @@
+const Events = {
+  Foo: {
+    Start: 'start',
+    Finish: 'finish',
+  },
+};
+
+module.exports = {Events};

utils/doclint/check_public_api/test/diff-events/foo.js

@@ -1,7 +1,3 @@
 class Foo {
 }
 
-Foo.Events = {
-  Start: 'start',
-  Finish: 'finish',
-};

utils/doclint/check_public_api/test/js-builder-common/Events.js

@@ -0,0 +1,6 @@
+const Events = {
+  A: {
+    AnEvent: 'anevent'
+  },
+};
+module.exports = { Events };

utils/doclint/check_public_api/test/js-builder-common/foo.js

@@ -11,7 +11,3 @@ class A {
   async method(foo, bar) {
   }
 }
-
-A.Events = {
-  AnEvent: 'anevent'
-};

utils/doclint/check_public_api/test/js-builder-inheritance/Events.js

@@ -0,0 +1,8 @@
+const Events = {
+  B: {
+    // Event with the same name as a super class method.
+    foo: 'foo',
+  },
+};
+
+module.exports = {Events};

utils/doclint/check_public_api/test/js-builder-inheritance/foo.js

@@ -13,8 +13,3 @@ class B extends A {
   bar(override) {
   }
 }
-
-B.Events = {
-  // Event with the same name as a super class method.
-  foo: 'foo'
-};