feat(events): allow waiting for removeAllListeners (#31941)

docs/src/api/class-browser.md

@@ -296,6 +296,18 @@ testing frameworks should explicitly create [`method: Browser.newContext`] follo
 ### option: Browser.newPage.storageStatePath = %%-csharp-java-context-option-storage-state-path-%%
 * since: v1.9
 
+## async method: Browser.removeAllListeners
+* since: v1.47
+
+Removes all the listeners of the given type if the type is given. Otherwise removes all the listeners.
+
+### param: Browser.removeAllListeners.type
+* since: v1.47
+- `type` ?<[string]>
+
+### option: Browser.removeAllListeners.behavior = %%-remove-all-listeners-options-behavior-%%
+* since: v1.47
+
 ## async method: Browser.startTracing
 * since: v1.11
 * langs: java, js, python

docs/src/api/class-browsercontext.md

@@ -1016,6 +1016,18 @@ Creates a new page in the browser context.
 
 Returns all open pages in the context.
 
+## async method: BrowserContext.removeAllListeners
+* since: v1.47
+
+Removes all the listeners of the given type if the type is given. Otherwise removes all the listeners.
+
+### param: BrowserContext.removeAllListeners.type
+* since: v1.47
+- `type` ?<[string]>
+
+### option: BrowserContext.removeAllListeners.behavior = %%-remove-all-listeners-options-behavior-%%
+* since: v1.47
+
 ## property: BrowserContext.request
 * since: v1.16
 * langs:

docs/src/api/class-page.md

@@ -3340,6 +3340,17 @@ Specifies the maximum number of times this handler should be called. Unlimited b
 
 By default, after calling the handler Playwright will wait until the overlay becomes hidden, and only then Playwright will continue with the action/assertion that triggered the handler. This option allows to opt-out of this behavior, so that overlay can stay visible after the handler has run.
 
+## async method: Page.removeAllListeners
+* since: v1.47
+
+Removes all the listeners of the given type if the type is given. Otherwise removes all the listeners.
+
+### param: Page.removeAllListeners.type
+* since: v1.47
+- `type` ?<[string]>
+
+### option: Page.removeAllListeners.behavior = %%-remove-all-listeners-options-behavior-%%
+* since: v1.47
 
 ## async method: Page.removeLocatorHandler
 * since: v1.44

docs/src/api/params.md

@@ -781,6 +781,16 @@ Whether to allow sites to register Service workers. Defaults to `'allow'`.
 * `'allow'`: [Service Workers](https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API) can be registered.
 * `'block'`: Playwright will block all registration of Service Workers.
 
+## remove-all-listeners-options-behavior
+* langs: js
+* since: v1.47
+- `behavior` <[RemoveAllListenersBehavior]<"wait"|"ignoreErrors"|"default">>
+
+Specifies whether to wait for already running listeners and what to do if they throw errors:
+* `'default'` - do not wait for current listener calls (if any) to finish, if the listener throws, it may result in unhandled error
+* `'wait'` - wait for current listener calls (if any) to finish
+* `'ignoreErrors'` - do not wait for current listener calls (if any) to finish, all errors thrown by the listeners after removal are silently caught
+
 ## unroute-all-options-behavior
 * langs: js, csharp, python
 * since: v1.41
@@ -791,6 +801,7 @@ Specifies whether to wait for already running handlers and what to do if they th
 * `'wait'` - wait for current handler calls (if any) to finish
 * `'ignoreErrors'` - do not wait for current handler calls (if any) to finish, all errors thrown by the handlers after unrouting are silently caught
 
+
 ## select-options-values
 * langs: java, js, csharp
 - `values` <[null]|[string]|[ElementHandle]|[Array]<[string]>|[Object]|[Array]<[ElementHandle]>|[Array]<[Object]>>

packages/playwright-core/src/client/eventEmitter.ts

@@ -23,7 +23,7 @@
  */
 
 type EventType = string | symbol;
-type Listener = (...args: any[]) => void;
+type Listener = (...args: any[]) => any;
 type EventMap = Record<EventType, Listener | Listener[]>;
 import { EventEmitter as OriginalEventEmitter } from 'events';
 import type { EventEmitter as EventEmitterType } from 'events';
@@ -34,6 +34,8 @@ export class EventEmitter implements EventEmitterType {
   private _events: EventMap | undefined = undefined;
   private _eventsCount = 0;
   private _maxListeners: number | undefined = undefined;
+  readonly _pendingHandlers = new Map<EventType, Set<Promise<void>>>();
+  private _rejectionHandler: ((error: Error) => void) | undefined;
 
   constructor() {
     if (this._events === undefined || this._events === Object.getPrototypeOf(this)._events) {
@@ -66,17 +68,34 @@ export class EventEmitter implements EventEmitterType {
       return false;
 
     if (typeof handler === 'function') {
-      Reflect.apply(handler, this, args);
+      this._callHandler(type, handler, args);
     } else {
       const len = handler.length;
       const listeners = handler.slice();
       for (let i = 0; i < len; ++i)
-        Reflect.apply(listeners[i], this, args);
+        this._callHandler(type, listeners[i], args);
     }
-
     return true;
   }
 
+  private _callHandler(type: EventType, handler: Listener, args: any[]): void {
+    const promise = Reflect.apply(handler, this, args);
+    if (!(promise instanceof Promise))
+      return;
+    let set = this._pendingHandlers.get(type);
+    if (!set) {
+      set = new Set();
+      this._pendingHandlers.set(type, set);
+    }
+    set.add(promise);
+    promise.catch(e => {
+      if (this._rejectionHandler)
+        this._rejectionHandler(e);
+      else
+        throw e;
+    }).finally(() => set.delete(promise));
+  }
+
   addListener(type: EventType, listener: Listener): this {
     return this._addListener(type, listener, false);
   }
@@ -214,10 +233,34 @@ export class EventEmitter implements EventEmitterType {
     return this.removeListener(type, listener);
   }
 
-  removeAllListeners(type?: string): this {
+  removeAllListeners(type?: EventType): this;
+  removeAllListeners(type: EventType | undefined, options: { behavior?: 'wait'|'ignoreErrors'|'default' }): Promise<void>;
+  removeAllListeners(type?: string, options?: { behavior?: 'wait'|'ignoreErrors'|'default' }): this | Promise<void> {
+    this._removeAllListeners(type);
+    if (!options)
+      return this;
+
+    if (options.behavior === 'wait') {
+      const errors: Error[] = [];
+      this._rejectionHandler = error => errors.push(error);
+      // eslint-disable-next-line internal-playwright/await-promise-in-class-returns
+      return this._waitFor(type).then(() => {
+        if (errors.length)
+          throw errors[0];
+      });
+    }
+
+    if (options.behavior === 'ignoreErrors')
+      this._rejectionHandler = () => {};
+
+    // eslint-disable-next-line internal-playwright/await-promise-in-class-returns
+    return Promise.resolve();
+  }
+
+  private _removeAllListeners(type?: string) {
     const events = this._events;
     if (!events)
-      return this;
+      return;
 
     // not listening for removeListener, no need to emit
     if (!events.removeListener) {
@@ -230,7 +273,7 @@ export class EventEmitter implements EventEmitterType {
         else
           delete events[type];
       }
-      return this;
+      return;
     }
 
     // emit removeListener for all listeners on all events
@@ -241,12 +284,12 @@ export class EventEmitter implements EventEmitterType {
         key = keys[i];
         if (key === 'removeListener')
           continue;
-        this.removeAllListeners(key);
+        this._removeAllListeners(key);
       }
-      this.removeAllListeners('removeListener');
+      this._removeAllListeners('removeListener');
       this._events = Object.create(null);
       this._eventsCount = 0;
-      return this;
+      return;
     }
 
     const listeners = events[type];
@@ -258,8 +301,6 @@ export class EventEmitter implements EventEmitterType {
       for (let i = listeners.length - 1; i >= 0; i--)
         this.removeListener(type, listeners[i]);
     }
-
-    return this;
   }
 
   listeners(type: EventType): Listener[] {
@@ -286,6 +327,18 @@ export class EventEmitter implements EventEmitterType {
     return this._eventsCount > 0 && this._events ? Reflect.ownKeys(this._events) : [];
   }
 
+  private async _waitFor(type?: EventType) {
+    let promises: Promise<void>[] = [];
+    if (type) {
+      promises = [...(this._pendingHandlers.get(type) || [])];
+    } else {
+      promises = [];
+      for (const [, pending] of this._pendingHandlers)
+        promises.push(...pending);
+    }
+    await Promise.all(promises);
+  }
+
   private _listeners(target: EventEmitter, type: EventType, unwrap: boolean): Listener[] {
     const events = target._events;
 
@@ -310,7 +363,7 @@ function checkListener(listener: any) {
 
 class OnceWrapper {
   private _fired = false;
-  readonly wrapperFunction: (...args: any[]) => void;
+  readonly wrapperFunction: (...args: any[]) => Promise<void> | void;
   readonly _listener: Listener;
   private _eventEmitter: EventEmitter;
   private _eventType: EventType;

tests/library/events/listener-count.spec.ts

@@ -20,7 +20,6 @@
 // OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
 // USE OR OTHER DEALINGS IN THE SOFTWARE.
 
-import events from 'events';
 import { EventEmitter } from '../../../packages/playwright-core/lib/client/eventEmitter';
 import { test, expect } from '@playwright/test';
 
@@ -32,7 +31,6 @@ test('Listener count test', () => {
   // Allow any type
   emitter.on(123, () => {});
 
-  expect(events.listenerCount(emitter, 'foo')).toEqual(2);
   expect(emitter.listenerCount('foo')).toEqual(2);
   expect(emitter.listenerCount('bar')).toEqual(0);
   expect(emitter.listenerCount('baz')).toEqual(1);

tests/library/events/listeners.spec.ts

@@ -40,7 +40,7 @@ test('EventEmitter listeners with one listener', () => {
   expect(listeners).toHaveLength(1);
   expect(listeners[0]).toEqual(listener);
 
-  ee.removeAllListeners('foo');
+  void ee.removeAllListeners('foo');
   expect<Array<any>>(ee.listeners('foo')).toHaveLength(0);
 
   expect(Array.isArray(fooListeners)).toBeTruthy();

tests/library/events/modify-in-emit.spec.ts

@@ -72,7 +72,7 @@ test('add and remove listeners', () => {
   e.on('foo', callback1);
   e.on('foo', callback2);
   expect(e.listeners('foo')).toHaveLength(2);
-  e.removeAllListeners('foo');
+  void e.removeAllListeners('foo');
   expect(e.listeners('foo')).toHaveLength(0);
 });
 

tests/library/events/remove-all-listeners-wait.spec.ts

@@ -0,0 +1,80 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * 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.
+ */
+
+import { ManualPromise } from '../../../packages/playwright-core/lib/utils/manualPromise';
+import { EventEmitter } from '../../../packages/playwright-core/lib/client/eventEmitter';
+import { test, expect } from '@playwright/test';
+
+test('should not throw with ignoreErrors', async () => {
+  const ee = new EventEmitter();
+  const releaseHandler = new ManualPromise();
+  ee.on('console', async () => {
+    await releaseHandler;
+    throw new Error('Error in console handler');
+  });
+  ee.emit('console');
+  await ee.removeAllListeners('console', { behavior: 'ignoreErrors' });
+  releaseHandler.resolve();
+});
+
+test('should wait', async () => {
+  const ee = new EventEmitter();
+  const releaseHandler = new ManualPromise();
+  let value = 0;
+  ee.on('console', async () => {
+    await releaseHandler;
+    value = 42;
+  });
+  ee.emit('console');
+  const removePromise = ee.removeAllListeners('console', { behavior: 'wait' });
+  releaseHandler.resolve();
+  await removePromise;
+  expect(value).toBe(42);
+});
+
+test('should wait all', async () => {
+  const ee = new EventEmitter();
+  const releaseHandler = new ManualPromise();
+  const values = [];
+  ee.on('a', async () => {
+    await releaseHandler;
+    values.push(42);
+  });
+  ee.on('b', async () => {
+    await releaseHandler;
+    values.push(43);
+  });
+  ee.emit('a');
+  ee.emit('b');
+  const removePromise = ee.removeAllListeners(undefined, { behavior: 'wait' });
+  releaseHandler.resolve();
+  await removePromise;
+  expect(values).toEqual([42, 43]);
+});
+
+test('wait should throw', async () => {
+  const ee = new EventEmitter();
+  const releaseHandler = new ManualPromise();
+  ee.on('console', async () => {
+    await releaseHandler;
+    throw new Error('Error in handler');
+  });
+  ee.emit('console');
+  const removePromise = ee.removeAllListeners('console', { behavior: 'wait' });
+  releaseHandler.resolve();
+  await expect(removePromise).rejects.toThrow('Error in handler');
+});

tests/library/events/remove-all-listeners.spec.ts

@@ -58,8 +58,8 @@ test('listeners', () => {
   const barListeners = ee.listeners('bar');
   const bazListeners = ee.listeners('baz');
   ee.on('removeListener', expectWrapper(['bar', 'baz', 'baz']));
-  ee.removeAllListeners('bar');
+  void ee.removeAllListeners('bar');
-  ee.removeAllListeners('baz');
+  void ee.removeAllListeners('baz');
 
   let listeners = ee.listeners('foo');
   expect(Array.isArray(listeners)).toBeTruthy();
@@ -91,7 +91,7 @@ test('removeAllListeners removes all listeners', () => {
   ee.on('bar', () => { });
   ee.on('removeListener', expectWrapper(['foo', 'bar', 'removeListener']));
   ee.on('removeListener', expectWrapper(['foo', 'bar']));
-  ee.removeAllListeners();
+  void ee.removeAllListeners();
 
   let listeners = ee.listeners('foo');
   expect(Array.isArray(listeners)).toBeTruthy();
@@ -120,7 +120,7 @@ test('listener count after removeAllListeners', () => {
   ee.on('baz', () => { });
   ee.on('baz', () => { });
   expect(ee.listeners('baz').length).toEqual(expectLength + 1);
-  ee.removeAllListeners('baz');
+  void ee.removeAllListeners('baz');
   expect(ee.listeners('baz').length).toEqual(0);
 });
 

tests/library/events/subclass.spec.ts

@@ -28,7 +28,7 @@ class MyEE extends EventEmitter {
     super();
     this.once(1, cb);
     this.emit(1);
-    this.removeAllListeners();
+    void this.removeAllListeners();
   }
 }
 

tests/library/events/symbols.spec.ts

@@ -34,7 +34,7 @@ test('should support symbols', () => {
 
   ee.emit(foo);
 
-  ee.removeAllListeners();
+  void ee.removeAllListeners();
   expect(ee.listeners(foo).length).toEqual(0);
 
   ee.on(foo, listener);

tests/page/page-listeners.spec.ts

@@ -0,0 +1,67 @@
+/**
+ * Copyright 2018 Google Inc. All rights reserved.
+ * Modifications copyright (c) Microsoft Corporation.
+ *
+ * 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.
+ */
+
+import { ManualPromise } from '../../packages/playwright-core/lib/utils/manualPromise';
+import { test as it, expect } from './pageTest';
+
+// This test is mostly for type checking, the actual tests are in the library/events.
+
+it('should not throw with ignoreErrors', async ({ page }) => {
+  const reachedHandler = new ManualPromise();
+  const releaseHandler = new ManualPromise();
+  page.on('console', async () => {
+    reachedHandler.resolve();
+    await releaseHandler;
+    throw new Error('Error in console handler');
+  });
+  await page.evaluate('console.log(1)');
+  await reachedHandler;
+  await page.removeAllListeners('console', { behavior: 'ignoreErrors' });
+  releaseHandler.resolve();
+  await page.waitForTimeout(1000);
+});
+
+it('should wait', async ({ page }) => {
+  const reachedHandler = new ManualPromise();
+  const releaseHandler = new ManualPromise();
+  let value = 0;
+  page.on('console', async () => {
+    reachedHandler.resolve();
+    value = 42;
+  });
+  await page.evaluate('console.log(1)');
+  await reachedHandler;
+  const removePromise = page.removeAllListeners('console', { behavior: 'wait' });
+  releaseHandler.resolve();
+  await removePromise;
+  expect(value).toBe(42);
+});
+
+it('wait should throw', async ({ page }) => {
+  const reachedHandler = new ManualPromise();
+  const releaseHandler = new ManualPromise();
+  page.on('console', async () => {
+    reachedHandler.resolve();
+    await releaseHandler;
+    throw new Error('Error in handler');
+  });
+  await page.evaluate('console.log(1)');
+  await reachedHandler;
+  const removePromise = page.removeAllListeners('console', { behavior: 'wait' });
+  releaseHandler.resolve();
+  await expect(removePromise).rejects.toThrow('Error in handler');
+});

utils/doclint/missingDocs.js

@@ -56,7 +56,7 @@ module.exports = function lint(documentation, jsSources, apiFileName) {
       continue;
     }
     for (const member of cls.membersArray) {
-      if (member.kind === 'event')
+      if (member.kind === 'event' || member.alias === 'removeAllListeners')
         continue;
       const params = methods.get(member.alias);
       if (!params) {

utils/generate_types/overrides.d.ts

@@ -62,6 +62,9 @@ export interface Page {
 
   exposeBinding(name: string, playwrightBinding: (source: BindingSource, arg: JSHandle) => any, options: { handle: true }): Promise<void>;
   exposeBinding(name: string, playwrightBinding: (source: BindingSource, ...args: any[]) => any, options?: { handle?: boolean }): Promise<void>;
+
+  removeAllListeners(type?: string): this;
+  removeAllListeners(type: string | undefined, options: { behavior?: 'wait'|'ignoreErrors'|'default' }): Promise<void>;
 }
 
 export interface Frame {
@@ -101,6 +104,14 @@ export interface BrowserContext {
   exposeBinding(name: string, playwrightBinding: (source: BindingSource, ...args: any[]) => any, options?: { handle?: boolean }): Promise<void>;
 
   addInitScript<Arg>(script: PageFunction<Arg, any> | { path?: string, content?: string }, arg?: Arg): Promise<void>;
+
+  removeAllListeners(type?: string): this;
+  removeAllListeners(type: string | undefined, options: { behavior?: 'wait'|'ignoreErrors'|'default' }): Promise<void>;
+}
+
+export interface Browser {
+  removeAllListeners(type?: string): this;
+  removeAllListeners(type: string | undefined, options: { behavior?: 'wait'|'ignoreErrors'|'default' }): Promise<void>;
 }
 
 export interface Worker {