try to simplify types a bit

docs/api.md

@@ -3688,6 +3688,7 @@ const browser = await chromium.launch({  // Or 'firefox' or 'webkit'.
   - `dumpio` <[boolean]> Whether to pipe the browser process stdout and stderr into `process.stdout` and `process.stderr`. Defaults to `false`.
   - `env` <[Object]> Specify environment variables that will be visible to the browser. Defaults to `process.env`.
   - `devtools` <[boolean]> **Chromium-only** Whether to auto-open a Developer Tools panel for each tab. If this option is `true`, the `headless` option will be set `false`.
+  - `slowMo` <[number]> Slows down Playwright operations by the specified amount of milliseconds. Useful so that you can see what is going on. Defaults to 0.
 - returns: <[Promise]<[BrowserContext]>> Promise which resolves to the browser app instance.
 
 Launches browser instance that uses persistent storage located at `userDataDir`.

src/browser.ts

@@ -27,11 +27,6 @@ export interface Browser extends platform.EventEmitterType {
   _setDebugFunction(debugFunction: (message: string) => void): void;
 }
 
-export type ConnectOptions = {
-  slowMo?: number,
-  wsEndpoint: string
-};
-
 export async function createPageInNewContext(browser: Browser, options?: BrowserContextOptions): Promise<Page> {
   const context = await browser.newContext(options);
   const page = await context.newPage();

src/server/browserType.ts

@@ -14,7 +14,6 @@
  * limitations under the License.
  */
 
-import { ConnectOptions } from '../browser';
 import { BrowserContext } from '../browserContext';
 import { BrowserServer } from './browserServer';
 
@@ -24,7 +23,7 @@ export type BrowserArgOptions = {
   devtools?: boolean,
 };
 
-export type LaunchOptions = BrowserArgOptions & {
+type LaunchOptionsBase = BrowserArgOptions & {
   executablePath?: string,
   ignoreDefaultArgs?: boolean | string[],
   handleSIGINT?: boolean,
@@ -39,11 +38,17 @@ export type LaunchOptions = BrowserArgOptions & {
   env?: {[key: string]: string} | undefined
 };
 
+export type ConnectOptions = {
+  wsEndpoint: string,
+  slowMo?: number
+};
+export type LaunchOptions = LaunchOptionsBase & { slowMo?: number };
+export type LaunchServerOptions = LaunchOptionsBase & { port?: number };
 export interface BrowserType<Browser> {
   executablePath(): string;
   name(): string;
-  launch(options?: LaunchOptions & { slowMo?: number }): Promise<Browser>;
-  launchServer(options?: LaunchOptions & { port?: number }): Promise<BrowserServer>;
+  launch(options?: LaunchOptions): Promise<Browser>;
+  launchServer(options?: LaunchServerOptions): Promise<BrowserServer>;
   launchPersistentContext(userDataDir: string, options?: LaunchOptions): Promise<BrowserContext>;
   connect(options: ConnectOptions): Promise<Browser>;
 }

src/server/chromium.ts

@@ -18,15 +18,15 @@
 import * as fs from 'fs';
 import * as os from 'os';
 import * as path from 'path';
-import { debugError, helper } from '../helper';
+import { debugError, helper, assert } from '../helper';
 import { CRBrowser } from '../chromium/crBrowser';
 import * as platform from '../platform';
 import * as ws from 'ws';
 import { launchProcess } from '../server/processLauncher';
 import { kBrowserCloseMessageId } from '../chromium/crConnection';
 import { PipeTransport } from './pipeTransport';
-import { LaunchOptions, BrowserArgOptions, BrowserType } from './browserType';
-import { ConnectOptions, LaunchType } from '../browser';
+import { LaunchOptions, BrowserArgOptions, BrowserType, ConnectOptions, LaunchServerOptions } from './browserType';
+import { LaunchType } from '../browser';
 import { BrowserServer, WebSocketWrapper } from './browserServer';
 import { Events } from '../events';
 import { ConnectionTransport, ProtocolRequest } from '../transport';
@@ -45,28 +45,30 @@ export class Chromium implements BrowserType<CRBrowser> {
     return 'chromium';
   }
 
-  async launch(options?: LaunchOptions & { slowMo?: number }): Promise<CRBrowser> {
-    if (options && (options as any).userDataDir)
-      throw new Error('userDataDir option is not supported in `browserType.launch`. Use `browserType.launchPersistentContext` instead');
+  async launch(options: LaunchOptions = {}): Promise<CRBrowser> {
+    assert(!(options as any).userDataDir, 'userDataDir option is not supported in `browserType.launch`. Use `browserType.launchPersistentContext` instead');
     const { browserServer, transport } = await this._launchServer(options, 'local');
-    const browser = await CRBrowser.connect(transport!, false, options && options.slowMo);
+    const browser = await CRBrowser.connect(transport!, false, options.slowMo);
     (browser as any)['__server__'] = browserServer;
     return browser;
   }
 
-  async launchServer(options?: LaunchOptions & { port?: number }): Promise<BrowserServer> {
-    return (await this._launchServer(options, 'server', undefined, options && options.port)).browserServer;
+  async launchServer(options: LaunchServerOptions = {}): Promise<BrowserServer> {
+    return (await this._launchServer(options, 'server')).browserServer;
   }
 
-  async launchPersistentContext(userDataDir: string, options?: LaunchOptions): Promise<BrowserContext> {
-    const { timeout = 30000 } = options || {};
+  async launchPersistentContext(userDataDir: string, options: LaunchOptions = {}): Promise<BrowserContext> {
+    const {
+      timeout = 30000,
+      slowMo = undefined
+    } = options;
     const { transport } = await this._launchServer(options, 'persistent', userDataDir);
-    const browser = await CRBrowser.connect(transport!, true);
+    const browser = await CRBrowser.connect(transport!, true, slowMo);
     await helper.waitWithTimeout(browser._firstPagePromise, 'first page', timeout);
     return browser._defaultContext;
   }
 
-  private async _launchServer(options: LaunchOptions = {}, launchType: LaunchType, userDataDir?: string, port?: number): Promise<{ browserServer: BrowserServer, transport?: ConnectionTransport }> {
+  private async _launchServer(options: LaunchServerOptions, launchType: LaunchType, userDataDir?: string): Promise<{ browserServer: BrowserServer, transport?: ConnectionTransport }> {
     const {
       ignoreDefaultArgs = false,
       args = [],
@@ -76,7 +78,9 @@ export class Chromium implements BrowserType<CRBrowser> {
       handleSIGINT = true,
       handleSIGTERM = true,
       handleSIGHUP = true,
+      port = 0,
     } = options;
+    assert(!port || launchType === 'server', 'Cannot specify a port without launching as a server.');
 
     let temporaryUserDataDir: string | null = null;
     if (!userDataDir) {
@@ -124,7 +128,7 @@ export class Chromium implements BrowserType<CRBrowser> {
     let transport: PipeTransport | undefined = undefined;
     let browserServer: BrowserServer | undefined = undefined;
     transport = new PipeTransport(launchedProcess.stdio[3] as NodeJS.WritableStream, launchedProcess.stdio[4] as NodeJS.ReadableStream, () => browserServer!.close());
-    browserServer = new BrowserServer(launchedProcess, gracefullyClose, launchType === 'server' ? wrapTransportWithWebSocket(transport, port || 0) : null);
+    browserServer = new BrowserServer(launchedProcess, gracefullyClose, launchType === 'server' ? wrapTransportWithWebSocket(transport, port) : null);
     return { browserServer, transport };
   }
 

src/server/firefox.ts

@@ -19,16 +19,16 @@ import * as fs from 'fs';
 import * as os from 'os';
 import * as path from 'path';
 import * as ws from 'ws';
-import { ConnectOptions, LaunchType } from '../browser';
+import { LaunchType } from '../browser';
 import { BrowserContext } from '../browserContext';
 import { TimeoutError } from '../errors';
 import { Events } from '../events';
 import { FFBrowser } from '../firefox/ffBrowser';
 import { kBrowserCloseMessageId } from '../firefox/ffConnection';
-import { debugError, helper } from '../helper';
+import { debugError, helper, assert } from '../helper';
 import * as platform from '../platform';
 import { BrowserServer, WebSocketWrapper } from './browserServer';
-import { BrowserArgOptions, BrowserType, LaunchOptions } from './browserType';
+import { BrowserArgOptions, BrowserType, LaunchOptions, LaunchServerOptions, ConnectOptions } from './browserType';
 import { launchProcess, waitForLine } from './processLauncher';
 import { ConnectionTransport, SequenceNumberMixer } from '../transport';
 
@@ -47,28 +47,30 @@ export class Firefox implements BrowserType<FFBrowser> {
     return 'firefox';
   }
 
-  async launch(options?: LaunchOptions & { slowMo?: number }): Promise<FFBrowser> {
-    if (options && (options as any).userDataDir)
-      throw new Error('userDataDir option is not supported in `browserType.launch`. Use `browserType.launchPersistentContext` instead');
+  async launch(options: LaunchOptions = {}): Promise<FFBrowser> {
+    assert(!(options as any).userDataDir, 'userDataDir option is not supported in `browserType.launch`. Use `browserType.launchPersistentContext` instead');
     const browserServer = await this._launchServer(options, 'local');
     const browser = await platform.connectToWebsocket(browserServer.wsEndpoint()!, transport => {
-      return FFBrowser.connect(transport, false, options && options.slowMo);
+      return FFBrowser.connect(transport, false, options.slowMo);
     });
     // Hack: for typical launch scenario, ensure that close waits for actual process termination.
     browser.close = () => browserServer.close();
     (browser as any)['__server__'] = browserServer;
     return browser;
   }
 
-  async launchServer(options?: LaunchOptions & { port?: number }): Promise<BrowserServer> {
-    return await this._launchServer(options, 'server', undefined, options && options.port);
+  async launchServer(options: LaunchServerOptions = {}): Promise<BrowserServer> {
+    return await this._launchServer(options, 'server');
   }
 
-  async launchPersistentContext(userDataDir: string, options?: LaunchOptions): Promise<BrowserContext> {
-    const { timeout = 30000 } = options || {};
+  async launchPersistentContext(userDataDir: string, options: LaunchOptions = {}): Promise<BrowserContext> {
+    const {
+      timeout = 30000,
+      slowMo = undefined,
+    } = options;
     const browserServer = await this._launchServer(options, 'persistent', userDataDir);
     const browser = await platform.connectToWebsocket(browserServer.wsEndpoint()!, transport => {
-      return FFBrowser.connect(transport, true);
+      return FFBrowser.connect(transport, true, slowMo);
     });
     await helper.waitWithTimeout(browser._firstPagePromise, 'first page', timeout);
     // Hack: for typical launch scenario, ensure that close waits for actual process termination.
@@ -77,7 +79,7 @@ export class Firefox implements BrowserType<FFBrowser> {
     return browserContext;
   }
 
-  private async _launchServer(options: LaunchOptions = {}, launchType: LaunchType, userDataDir?: string, port?: number): Promise<BrowserServer> {
+  private async _launchServer(options: LaunchServerOptions, launchType: LaunchType, userDataDir?: string): Promise<BrowserServer> {
     const {
       ignoreDefaultArgs = false,
       args = [],
@@ -88,7 +90,9 @@ export class Firefox implements BrowserType<FFBrowser> {
       handleSIGINT = true,
       handleSIGTERM = true,
       timeout = 30000,
+      port = 0,
     } = options;
+    assert(!port || launchType === 'server', 'Cannot specify a port without launching as a server.');
 
     const firefoxArguments = [];
 
@@ -145,7 +149,7 @@ export class Firefox implements BrowserType<FFBrowser> {
 
     let browserServer: BrowserServer | undefined = undefined;
     let browserWSEndpoint: string | undefined = undefined;
-    const webSocketWrapper = launchType === 'server' ? (await platform.connectToWebsocket(innerEndpoint, t => wrapTransportWithWebSocket(t, port || 0))) : new WebSocketWrapper(innerEndpoint, []);
+    const webSocketWrapper = launchType === 'server' ? (await platform.connectToWebsocket(innerEndpoint, t => wrapTransportWithWebSocket(t, port))) : new WebSocketWrapper(innerEndpoint, []);
     browserWSEndpoint = webSocketWrapper.wsEndpoint;
     browserServer = new BrowserServer(launchedProcess, gracefullyClose, webSocketWrapper);
     return browserServer;

src/server/webkit.ts

@@ -22,12 +22,12 @@ import * as fs from 'fs';
 import * as path from 'path';
 import * as platform from '../platform';
 import * as os from 'os';
-import { debugError, helper } from '../helper';
+import { debugError, helper, assert } from '../helper';
 import { kBrowserCloseMessageId } from '../webkit/wkConnection';
-import { LaunchOptions, BrowserArgOptions, BrowserType } from './browserType';
+import { LaunchOptions, BrowserArgOptions, BrowserType, LaunchServerOptions, ConnectOptions } from './browserType';
 import { ConnectionTransport, SequenceNumberMixer } from '../transport';
 import * as ws from 'ws';
-import { ConnectOptions, LaunchType } from '../browser';
+import { LaunchType } from '../browser';
 import { BrowserServer, WebSocketWrapper } from './browserServer';
 import { Events } from '../events';
 import { BrowserContext } from '../browserContext';
@@ -45,28 +45,30 @@ export class WebKit implements BrowserType<WKBrowser> {
     return 'webkit';
   }
 
-  async launch(options?: LaunchOptions & { slowMo?: number }): Promise<WKBrowser> {
-    if (options && (options as any).userDataDir)
-      throw new Error('userDataDir option is not supported in `browserType.launch`. Use `browserType.launchPersistentContext` instead');
+  async launch(options: LaunchOptions = {}): Promise<WKBrowser> {
+    assert(!(options as any).userDataDir, 'userDataDir option is not supported in `browserType.launch`. Use `browserType.launchPersistentContext` instead');
     const { browserServer, transport } = await this._launchServer(options, 'local');
-    const browser = await WKBrowser.connect(transport!, options && options.slowMo);
+    const browser = await WKBrowser.connect(transport!, options.slowMo);
     (browser as any)['__server__'] = browserServer;
     return browser;
   }
 
-  async launchServer(options?: LaunchOptions & { port?: number }): Promise<BrowserServer> {
-    return (await this._launchServer(options, 'server', undefined, options && options.port)).browserServer;
+  async launchServer(options: LaunchServerOptions = {}): Promise<BrowserServer> {
+    return (await this._launchServer(options, 'server')).browserServer;
   }
 
-  async launchPersistentContext(userDataDir: string, options?: LaunchOptions): Promise<BrowserContext> {
-    const { timeout = 30000 } = options || {};
+  async launchPersistentContext(userDataDir: string, options: LaunchOptions = {}): Promise<BrowserContext> {
+    const {
+      timeout = 30000,
+      slowMo = undefined,
+    } = options;
     const { transport } = await this._launchServer(options, 'persistent', userDataDir);
-    const browser = await WKBrowser.connect(transport!, undefined, true);
+    const browser = await WKBrowser.connect(transport!, slowMo, true);
     await helper.waitWithTimeout(browser._waitForFirstPageTarget(), 'first page', timeout);
     return browser._defaultContext;
   }
 
-  private async _launchServer(options: LaunchOptions = {}, launchType: LaunchType, userDataDir?: string, port?: number): Promise<{ browserServer: BrowserServer, transport?: ConnectionTransport }> {
+  private async _launchServer(options: LaunchServerOptions, launchType: LaunchType, userDataDir?: string): Promise<{ browserServer: BrowserServer, transport?: ConnectionTransport }> {
     const {
       ignoreDefaultArgs = false,
       args = [],
@@ -76,7 +78,9 @@ export class WebKit implements BrowserType<WKBrowser> {
       handleSIGINT = true,
       handleSIGTERM = true,
       handleSIGHUP = true,
+      port = 0,
     } = options;
+    assert(!port || launchType === 'server', 'Cannot specify a port without launching as a server.');
 
     let temporaryUserDataDir: string | null = null;
     if (!userDataDir) {
@@ -86,9 +90,9 @@ export class WebKit implements BrowserType<WKBrowser> {
 
     const webkitArguments = [];
     if (!ignoreDefaultArgs)
-      webkitArguments.push(...this._defaultArgs(options, launchType, userDataDir!, port || 0));
+      webkitArguments.push(...this._defaultArgs(options, launchType, userDataDir!, port));
     else if (Array.isArray(ignoreDefaultArgs))
-      webkitArguments.push(...this._defaultArgs(options, launchType, userDataDir!, port || 0).filter(arg => ignoreDefaultArgs.indexOf(arg) === -1));
+      webkitArguments.push(...this._defaultArgs(options, launchType, userDataDir!, port).filter(arg => ignoreDefaultArgs.indexOf(arg) === -1));
     else
       webkitArguments.push(...args);
 

utils/generate_types/overrides.d.ts

@@ -173,3 +173,4 @@ class TimeoutError extends Error {}
 
 export const selectors: Selectors;
 export const devices: {[name: string]: DeviceDescriptor} & DeviceDescriptor[];
+w