fix(types): fix parameters where they disagree with the api (#3525)

docs/api.md

@@ -451,6 +451,7 @@ puppeteer.launch().then(async browser => {
     - `hasTouch`<[boolean]> Specifies if viewport supports touch events. Defaults to `false`
     - `isLandscape` <[boolean]> Specifies if viewport is in landscape mode. Defaults to `false`.
   - `slowMo` <[number]> Slows down Puppeteer operations by the specified amount of milliseconds. Useful so that you can see what is going on.
+  - `transport` <[ConnectionTransport]> **Experimental** Specify a custom transport object for Puppeteer to use.
 - returns: <[Promise]<[Browser]>>
 
 This methods attaches Puppeteer to an existing Chromium instance.
@@ -489,7 +490,7 @@ The default flags that Chromium will be launched with.
     - `hasTouch`<[boolean]> Specifies if viewport supports touch events. Defaults to `false`
     - `isLandscape` <[boolean]> Specifies if viewport is in landscape mode. Defaults to `false`.
   - `args` <[Array]<[string]>> Additional arguments to pass to the browser instance. The list of Chromium flags can be found [here](http://peter.sh/experiments/chromium-command-line-switches/).
-  - `ignoreDefaultArgs` <([boolean]|<[Array]<[string]>>)> If `true`, then do not use [`puppeteer.defaultArgs()`](#puppeteerdefaultargs-options). If an array is given, then filter out the given default arguments. Dangerous option; use with care. Defaults to `false`.
+  - `ignoreDefaultArgs` <[boolean]|[Array]<[string]>> If `true`, then do not use [`puppeteer.defaultArgs()`](#puppeteerdefaultargs-options). If an array is given, then filter out the given default arguments. Dangerous option; use with care. Defaults to `false`.
   - `handleSIGINT` <[boolean]> Close the browser process on Ctrl-C. Defaults to `true`.
   - `handleSIGTERM` <[boolean]> Close the browser process on SIGTERM. Defaults to `true`.
   - `handleSIGHUP` <[boolean]> Close the browser process on SIGHUP. Defaults to `true`.
@@ -1145,10 +1146,11 @@ Gets the full HTML contents of the page, including the doctype.
   - `domain` <[string]>
   - `path` <[string]>
   - `expires` <[number]> Unix time in seconds.
+  - `size` <[number]>
   - `httpOnly` <[boolean]>
   - `secure` <[boolean]>
   - `session` <[boolean]>
-  - `sameSite` <[string]> `"Strict"` or `"Lax"`.
+  - `sameSite` <"Strict"|"Lax">
 
 If no URLs are specified, this method returns cookies for the current page URL.
 If URLs are specified, only cookies for those URLs are returned.
@@ -1163,7 +1165,6 @@ If URLs are specified, only cookies for those URLs are returned.
   - `url` <[string]>
   - `domain` <[string]>
   - `path` <[string]>
-  - `secure` <[boolean]>
 - returns: <[Promise]>
 
 #### page.emulate(options)
@@ -1424,7 +1425,7 @@ Shortcut for [page.mainFrame().hover(selector)](#framehoverselector).
 
 #### page.isClosed()
 
-- returns: boolean
+- returns: <[boolean]>
 
 Indicates that the page has been closed.
 
@@ -1475,13 +1476,13 @@ Page is guaranteed to have a main frame which persists during navigations.
   - `landscape` <[boolean]> Paper orientation. Defaults to `false`.
   - `pageRanges` <[string]> Paper ranges to print, e.g., '1-5, 8, 11-13'. Defaults to the empty string, which means print all pages.
   - `format` <[string]> Paper format. If set, takes priority over `width` or `height` options. Defaults to 'Letter'.
-  - `width` <[string]> Paper width, accepts values labeled with units.
+  - `width` <[string]|[number]> Paper width, accepts values labeled with units.
-  - `height` <[string]> Paper height, accepts values labeled with units.
+  - `height` <[string]|[number]> Paper height, accepts values labeled with units.
   - `margin` <[Object]> Paper margins, defaults to none.
-    - `top` <[string]> Top margin, accepts values labeled with units.
+    - `top` <[string]|[number]> Top margin, accepts values labeled with units.
-    - `right` <[string]> Right margin, accepts values labeled with units.
+    - `right` <[string]|[number]> Right margin, accepts values labeled with units.
-    - `bottom` <[string]> Bottom margin, accepts values labeled with units.
+    - `bottom` <[string]|[number]> Bottom margin, accepts values labeled with units.
-    - `left` <[string]> Left margin, accepts values labeled with units.
+    - `left` <[string]|[number]> Left margin, accepts values labeled with units.
   - `preferCSSPageSize` <[boolean]> Give any CSS `@page` size declared in the page priority over what is declared in `width` and `height` or `format` options. Defaults to `false`, which will scale the content to fit the paper size.
 - returns: <[Promise]<[Buffer]>> Promise which resolves with PDF buffer.
 
@@ -1619,7 +1620,7 @@ Toggles ignoring cache for each request based on the enabled state. By default,
   - `expires` <[number]> Unix time in seconds.
   - `httpOnly` <[boolean]>
   - `secure` <[boolean]>
-  - `sameSite` <[string]> `"Strict"` or `"Lax"`.
+  - `sameSite` <"Strict"|"Lax">
 - returns: <[Promise]>
 
 ```js
@@ -2004,7 +2005,7 @@ Most of the accessibility tree gets filtered out when converting from Blink AX T
 #### accessibility.snapshot([options])
 - `options` <[Object]>
   - `interestingOnly` <[boolean]> Prune uninteresting nodes from the tree. Defaults to `true`.
-- returns: <[Promise]<[AXNode]>> Returns an AXNode object with the following properties:
+- returns: <[Promise]<[Object]>> Returns an [AXNode] object with the following properties:
   - `role` <[string]> The [role](https://www.w3.org/TR/wai-aria/#usage_intro).
   - `name` <[string]> A human readable name for the node.
   - `value` <[string]|[number]> The current value of the node.
@@ -2021,8 +2022,8 @@ Most of the accessibility tree gets filtered out when converting from Blink AX T
   - `readonly` <[boolean]> Whether the node is read only.
   - `required` <[boolean]> Whether the node is required.
   - `selected` <[boolean]> Whether the node is selected in its parent node.
-  - `checked` <[boolean]|[string]> Whether the checkbox is checked, or "mixed".
+  - `checked` <[boolean]|"mixed"> Whether the checkbox is checked, or "mixed".
-  - `pressed` <[boolean]|[string]> Whether the toggle button is checked, or "mixed".
+  - `pressed` <[boolean]|"mixed"> Whether the toggle button is checked, or "mixed".
   - `level` <[number]> The level of a heading.
   - `valuemin` <[number]> The minimum value in a node.
   - `valuemax` <[number]> The maximum value in a node.
@@ -2030,7 +2031,7 @@ Most of the accessibility tree gets filtered out when converting from Blink AX T
   - `haspopup` <[string]> What kind of popup is currently being shown for a node.
   - `invalid` <[string]> Whether and in what way this node's value is invalid.
   - `orientation` <[string]> Whether the node is oriented horizontally or vertically.
-  - `children` <[Array]<[AXNode]>> Child nodes of this node, if any.
+  - `children` <[Array]<[Object]>> Child [AXNode]s of this node, if any.
 
 Captures the current state of the accessibility tree. The returned object represents the root accessible node of the page.
 
@@ -2841,7 +2842,7 @@ Returns either `null` or the object handle itself, if the object handle is an in
 The `jsHandle.dispose` method stops referencing the element handle.
 
 #### jsHandle.executionContext()
-- returns: [ExecutionContext]
+- returns: <[ExecutionContext]>
 
 Returns execution context the handle belongs to.
 
@@ -2966,10 +2967,18 @@ This method returns the bounding box of the element (relative to the main frame)
 
 #### elementHandle.boxModel()
 - returns: <[Promise]<?[Object]>>
-  - content <[Array]<[Object]>> Content box, represented as an array of {x, y} points.
+  - content <[Array]<[Object]>> Content box.
-  - padding <[Array]<[Object]>> Padding box, represented as an array of {x, y} points.
+    - x <[number]>
-  - border <[Array]<[Object]>> Border box, represented as an array of {x, y} points.
+    - y <[number]>
-  - margin <[Array]<[Object]>> Margin box, represented as an array of {x, y} points.
+  - padding <[Array]<[Object]>> Padding box.
+    - x <[number]>
+    - y <[number]>
+  - border <[Array]<[Object]>> Border box.
+    - x <[number]>
+    - y <[number]>
+  - margin <[Array]<[Object]>> Margin box.
+    - x <[number]>
+    - y <[number]>
   - width <[number]> Element's width.
   - height <[number]> Element's height.
 
@@ -2994,7 +3003,7 @@ If the element is detached from DOM, the method throws an error.
 The `elementHandle.dispose` method stops referencing the element handle.
 
 #### elementHandle.executionContext()
-- returns: [ExecutionContext]
+- returns: <[ExecutionContext]>
 
 #### elementHandle.focus()
 - returns: <[Promise]>
@@ -3224,7 +3233,7 @@ ResourceType will be one of the following: `document`, `stylesheet`, `image`, `m
   - `status` <[number]> Response status code, defaults to `200`.
   - `headers` <[Object]> Optional response headers
   - `contentType` <[string]> If set, equals to setting `Content-Type` response header
-  - `body` <[Buffer]|[string]> Optional response body
+  - `body` <[string]|[Buffer]> Optional response body
 - returns: <[Promise]>
 
 Fulfills request with given response. To use this, request interception should
@@ -3524,3 +3533,4 @@ TimeoutError is emitted whenever certain operations are terminated due to timeou
 [Worker]: #class-worker "Worker"
 [Accessibility]: #class-accessibility "Accessibility"
 [AXNode]: #accessibilitysnapshotoptions "AXNode"
+[ConnectionTransport]: ../lib/WebSocketTransport.js "ConnectionTransport"

lib/Coverage.js

@@ -35,7 +35,7 @@ class Coverage {
   }
 
   /**
-   * @param {!Object} options
+   * @param {!{resetOnNavigation?: boolean, reportAnonymousScripts?: boolean}} options
    */
   async startJSCoverage(options) {
     return await this._jsCoverage.start(options);
@@ -49,7 +49,7 @@ class Coverage {
   }
 
   /**
-   * @param {!Object} options
+   * @param {{resetOnNavigation?: boolean}=} options
    */
   async startCSSCoverage(options) {
     return await this._cssCoverage.start(options);
@@ -80,12 +80,16 @@ class JSCoverage {
   }
 
   /**
-   * @param {!Object} options
+   * @param {!{resetOnNavigation?: boolean, reportAnonymousScripts?: boolean}} options
    */
   async start(options = {}) {
     assert(!this._enabled, 'JSCoverage is already enabled');
-    this._resetOnNavigation = options.resetOnNavigation === undefined ? true : !!options.resetOnNavigation;
+    const {
-    this._reportAnonymousScripts = !!options.reportAnonymousScripts;
+      resetOnNavigation = true,
+      reportAnonymousScripts = false
+    } = options;
+    this._resetOnNavigation = resetOnNavigation;
+    this._reportAnonymousScripts = reportAnonymousScripts;
     this._enabled = true;
     this._scriptURLs.clear();
     this._scriptSources.clear();
@@ -174,11 +178,12 @@ class CSSCoverage {
   }
 
   /**
-   * @param {!Object} options
+   * @param {{resetOnNavigation?: boolean}=} options
    */
   async start(options = {}) {
     assert(!this._enabled, 'CSSCoverage is already enabled');
-    this._resetOnNavigation = options.resetOnNavigation === undefined ? true : !!options.resetOnNavigation;
+    const {resetOnNavigation = true} = options;
+    this._resetOnNavigation = resetOnNavigation;
     this._enabled = true;
     this._stylesheetURLs.clear();
     this._stylesheetSources.clear();

lib/ExecutionContext.js

@@ -376,7 +376,7 @@ class ElementHandle extends JSHandle {
 
   /**
    * @param {!Array<number>} quad
-   * @return {!Array<object>}
+   * @return {!Array<{x: number, y: number}>}
    */
   _fromProtocolQuad(quad) {
     return [
@@ -394,9 +394,9 @@ class ElementHandle extends JSHandle {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{delay?: number, button?: "left"|"right"|"middle", clickCount?: number}=} options
    */
-  async click(options = {}) {
+  async click(options) {
     await this._scrollIntoViewIfNeeded();
     const {x, y} = await this._clickablePoint();
     await this._page.mouse.click(x, y, options);
@@ -432,7 +432,7 @@ class ElementHandle extends JSHandle {
 
   /**
    * @param {string} key
-   * @param {!Object=} options
+   * @param {!{delay?: number, text?: string}=} options
    */
   async press(key, options) {
     await this.focus();
@@ -458,7 +458,7 @@ class ElementHandle extends JSHandle {
   }
 
   /**
-   * @return {!Promise<?object>}
+   * @return {!Promise<?BoxModel>}
    */
   async boxModel() {
     const result = await this._getBoxModel();
@@ -646,6 +646,16 @@ function computeQuadArea(quad) {
   return Math.abs(area);
 }
 
+/**
+ * @typedef {Object} BoxModel
+ * @property {!Array<!{x: number, y: number}>} content
+ * @property {!Array<!{x: number, y: number}>} padding
+ * @property {!Array<!{x: number, y: number}>} border
+ * @property {!Array<!{x: number, y: number}>} margin
+ * @property {number} width
+ * @property {number} height
+ */
+
 helper.tracePublicAPI(ElementHandle);
 helper.tracePublicAPI(JSHandle);
 helper.tracePublicAPI(ExecutionContext);

lib/FrameManager.js

@@ -65,17 +65,19 @@ class FrameManager extends EventEmitter {
   /**
    * @param {!Puppeteer.Frame} frame
    * @param {string} url
-   * @param {!Object=} options
+   * @param {!{referer?: string, timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
   async navigateFrame(frame, url, options = {}) {
-    const referrer = typeof options.referer === 'string' ? options.referer : this._networkManager.extraHTTPHeaders()['referer'];
+    const {
+      referer = this._networkManager.extraHTTPHeaders()['referer'],
+      timeout = this._defaultNavigationTimeout,
+    } = options;
 
-    const timeout = typeof options.timeout === 'number' ? options.timeout : this._defaultNavigationTimeout;
     const watcher = new NavigatorWatcher(this._client, this, this._networkManager, frame, timeout, options);
     let ensureNewDocumentNavigation = false;
     let error = await Promise.race([
-      navigate(this._client, url, referrer, frame._id),
+      navigate(this._client, url, referer, frame._id),
       watcher.timeoutOrTerminationPromise(),
     ]);
     if (!error) {
@@ -109,11 +111,13 @@ class FrameManager extends EventEmitter {
 
   /**
    * @param {!Puppeteer.Frame} frame
-   * @param {!Object=} options
+   * @param {!{timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
-  async waitForFrameNavigation(frame, options) {
+  async waitForFrameNavigation(frame, options = {}) {
-    const timeout = typeof options.timeout === 'number' ? options.timeout : this._defaultNavigationTimeout;
+    const {
+      timeout = this._defaultNavigationTimeout
+    } = options;
     const watcher = new NavigatorWatcher(this._client, this, this._networkManager, frame, timeout, options);
     const error = await Promise.race([
       watcher.timeoutOrTerminationPromise(),
@@ -397,18 +401,18 @@ class Frame {
 
   /**
    * @param {string} url
-   * @param {!Object=} options
+   * @param {!{referer?: string, timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
-  async goto(url, options = {}) {
+  async goto(url, options) {
     return await this._frameManager.navigateFrame(this, url, options);
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
-  async waitForNavigation(options = {}) {
+  async waitForNavigation(options) {
     return await this._frameManager.waitForFrameNavigation(this, options);
   }
 
@@ -566,30 +570,35 @@ class Frame {
   }
 
   /**
-   * @param {Object} options
+   * @param {!{url?: string, path?: string, content?: string, type?: string}} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   async addScriptTag(options) {
-    if (typeof options.url === 'string') {
+    const {
-      const url = options.url;
+      url = null,
+      path = null,
+      content = null,
+      type = ''
+    } = options;
+    if (url !== null) {
       try {
         const context = await this._contextPromise;
-        return (await context.evaluateHandle(addScriptUrl, url, options.type)).asElement();
+        return (await context.evaluateHandle(addScriptUrl, url, type)).asElement();
       } catch (error) {
         throw new Error(`Loading script from ${url} failed`);
       }
     }
 
-    if (typeof options.path === 'string') {
+    if (path !== null) {
-      let contents = await readFileAsync(options.path, 'utf8');
+      let contents = await readFileAsync(path, 'utf8');
-      contents += '//# sourceURL=' + options.path.replace(/\n/g, '');
+      contents += '//# sourceURL=' + path.replace(/\n/g, '');
       const context = await this._contextPromise;
-      return (await context.evaluateHandle(addScriptContent, contents, options.type)).asElement();
+      return (await context.evaluateHandle(addScriptContent, contents, type)).asElement();
     }
 
-    if (typeof options.content === 'string') {
+    if (content !== null) {
       const context = await this._contextPromise;
-      return (await context.evaluateHandle(addScriptContent, options.content, options.type)).asElement();
+      return (await context.evaluateHandle(addScriptContent, content, type)).asElement();
     }
 
     throw new Error('Provide an object with a `url`, `path` or `content` property');
@@ -632,12 +641,16 @@ class Frame {
   }
 
   /**
-   * @param {Object} options
+   * @param {!{url?: string, path?: string, content?: string}} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   async addStyleTag(options) {
-    if (typeof options.url === 'string') {
+    const {
-      const url = options.url;
+      url = null,
+      path = null,
+      content = null
+    } = options;
+    if (url !== null) {
       try {
         const context = await this._contextPromise;
         return (await context.evaluateHandle(addStyleUrl, url)).asElement();
@@ -646,16 +659,16 @@ class Frame {
       }
     }
 
-    if (typeof options.path === 'string') {
+    if (path !== null) {
-      let contents = await readFileAsync(options.path, 'utf8');
+      let contents = await readFileAsync(path, 'utf8');
-      contents += '/*# sourceURL=' + options.path.replace(/\n/g, '') + '*/';
+      contents += '/*# sourceURL=' + path.replace(/\n/g, '') + '*/';
       const context = await this._contextPromise;
       return (await context.evaluateHandle(addStyleContent, contents)).asElement();
     }
 
-    if (typeof options.content === 'string') {
+    if (content !== null) {
       const context = await this._contextPromise;
-      return (await context.evaluateHandle(addStyleContent, options.content)).asElement();
+      return (await context.evaluateHandle(addStyleContent, content)).asElement();
     }
 
     throw new Error('Provide an object with a `url`, `path` or `content` property');
@@ -697,9 +710,9 @@ class Frame {
 
   /**
    * @param {string} selector
-   * @param {!Object=} options
+   * @param {!{delay?: number, button?: "left"|"right"|"middle", clickCount?: number}=} options
    */
-  async click(selector, options = {}) {
+  async click(selector, options) {
     const handle = await this.$(selector);
     assert(handle, 'No node found for selector: ' + selector);
     await handle.click(options);
@@ -797,30 +810,32 @@ class Frame {
 
   /**
    * @param {string} selector
-   * @param {!Object=} options
+   * @param {!{visible?: boolean, hidden?: boolean, timeout?: number}=} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
-  waitForSelector(selector, options = {}) {
+  waitForSelector(selector, options) {
     return this._waitForSelectorOrXPath(selector, false, options);
   }
 
   /**
    * @param {string} xpath
-   * @param {!Object=} options
+   * @param {!{visible?: boolean, hidden?: boolean, timeout?: number}=} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
-  waitForXPath(xpath, options = {}) {
+  waitForXPath(xpath, options) {
     return this._waitForSelectorOrXPath(xpath, true, options);
   }
 
   /**
    * @param {Function|string} pageFunction
-   * @param {!Object=} options
+   * @param {!{polling?: string|number, timeout?: number}=} options
    * @return {!Promise<!Puppeteer.JSHandle>}
    */
   waitForFunction(pageFunction, options = {}, ...args) {
-    const timeout = helper.isNumber(options.timeout) ? options.timeout : 30000;
+    const {
-    const polling = options.polling || 'raf';
+      polling = 'raf',
+      timeout = 30000
+    } = options;
     return new WaitTask(this, pageFunction, 'function', polling, timeout, ...args).promise;
   }
 
@@ -834,14 +849,16 @@ class Frame {
   /**
    * @param {string} selectorOrXPath
    * @param {boolean} isXPath
-   * @param {!Object=} options
+   * @param {!{visible?: boolean, hidden?: boolean, timeout?: number}=} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   _waitForSelectorOrXPath(selectorOrXPath, isXPath, options = {}) {
-    const waitForVisible = !!options.visible;
+    const {
-    const waitForHidden = !!options.hidden;
+      visible: waitForVisible = false,
+      hidden: waitForHidden = false,
+      timeout = 30000,
+    } = options;
     const polling = waitForVisible || waitForHidden ? 'raf' : 'mutation';
-    const timeout = helper.isNumber(options.timeout) ? options.timeout : 30000;
     const title = `${isXPath ? 'XPath' : 'selector'} "${selectorOrXPath}"${waitForHidden ? ' to be hidden' : ''}`;
     return new WaitTask(this, predicate, title, polling, timeout, selectorOrXPath, isXPath, waitForVisible, waitForHidden).promise;
 
@@ -1117,17 +1134,19 @@ class NavigatorWatcher {
    * @param {!NetworkManager} networkManager
    * @param {!Puppeteer.Frame} frame
    * @param {number} timeout
-   * @param {!Object=} options
+   * @param {!{waitUntil?: string|!Array<string>}} options
    */
   constructor(client, frameManager, networkManager, frame, timeout, options = {}) {
-    assert(options.networkIdleTimeout === undefined, 'ERROR: networkIdleTimeout option is no longer supported.');
+    assert(options['networkIdleTimeout'] === undefined, 'ERROR: networkIdleTimeout option is no longer supported.');
-    assert(options.networkIdleInflight === undefined, 'ERROR: networkIdleInflight option is no longer supported.');
+    assert(options['networkIdleInflight'] === undefined, 'ERROR: networkIdleInflight option is no longer supported.');
     assert(options.waitUntil !== 'networkidle', 'ERROR: "networkidle" option is no longer supported. Use "networkidle2" instead');
-    let waitUntil = ['load'];
+    let {
-    if (Array.isArray(options.waitUntil))
+      waitUntil = ['load']
-      waitUntil = options.waitUntil.slice();
+    } = options;
-    else if (typeof options.waitUntil === 'string')
+    if (Array.isArray(waitUntil))
-      waitUntil = [options.waitUntil];
+      waitUntil = waitUntil.slice();
+    else if (typeof waitUntil === 'string')
+      waitUntil = [waitUntil];
     this._expectedLifecycle = waitUntil.map(value => {
       const protocolEvent = puppeteerToProtocolLifecycle[value];
       assert(protocolEvent, 'Unknown value for options.waitUntil: ' + value);

lib/Input.js

@@ -171,11 +171,12 @@ class Keyboard {
 
   /**
    * @param {string} key
-   * @param {!Object=} options
+   * @param {!{delay?: number, text?: string}=} options
    */
-  async press(key, options) {
+  async press(key, options = {}) {
+    const {delay = null} = options;
     await this.down(key, options);
-    if (options && options.delay)
+    if (delay !== null)
       await new Promise(f => setTimeout(f, options.delay));
     await this.up(key);
   }
@@ -198,13 +199,13 @@ class Mouse {
   /**
    * @param {number} x
    * @param {number} y
-   * @param {Object=} options
+   * @param {!{steps?: number}=} options
    */
   async move(x, y, options = {}) {
+    const {steps = 1} = options;
     const fromX = this._x, fromY = this._y;
     this._x = x;
     this._y = y;
-    const steps = options.steps || 1;
     for (let i = 1; i <= steps; i++) {
       await this._client.send('Input.dispatchMouseEvent', {
         type: 'mouseMoved',
@@ -219,43 +220,46 @@ class Mouse {
   /**
    * @param {number} x
    * @param {number} y
-   * @param {!Object=} options
+   * @param {!{delay?: number, button?: "left"|"right"|"middle", clickCount?: number}=} options
    */
   async click(x, y, options = {}) {
+    const {delay = null} = options;
     this.move(x, y);
     this.down(options);
-    if (typeof options.delay === 'number')
+    if (delay !== null)
-      await new Promise(f => setTimeout(f, options.delay));
+      await new Promise(f => setTimeout(f, delay));
     await this.up(options);
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{button?: "left"|"right"|"middle", clickCount?: number}=} options
    */
   async down(options = {}) {
-    this._button = (options.button || 'left');
+    const {button = 'left', clickCount = 1} = options;
+    this._button = button;
     await this._client.send('Input.dispatchMouseEvent', {
       type: 'mousePressed',
-      button: this._button,
+      button,
       x: this._x,
       y: this._y,
       modifiers: this._keyboard._modifiers,
-      clickCount: (options.clickCount || 1)
+      clickCount
     });
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{button?: "left"|"right"|"middle", clickCount?: number}=} options
    */
   async up(options = {}) {
+    const {button = 'left', clickCount = 1} = options;
     this._button = 'none';
     await this._client.send('Input.dispatchMouseEvent', {
       type: 'mouseReleased',
-      button: (options.button || 'left'),
+      button,
       x: this._x,
       y: this._y,
       modifiers: this._keyboard._modifiers,
-      clickCount: (options.clickCount || 1)
+      clickCount
     });
   }
 }

lib/Launcher.js

@@ -71,7 +71,7 @@ class Launcher {
   }
 
   /**
-   * @param {!(LaunchOptions & ChromeArgOptions & BrowserOptions)=} options
+   * @param {!(Launcher.LaunchOptions & Launcher.ChromeArgOptions & Launcher.BrowserOptions)=} options
    * @return {!Promise<!Browser>}
    */
   async launch(options = {}) {
@@ -236,7 +236,7 @@ class Launcher {
   }
 
   /**
-   * @param {!ChromeArgOptions=} options
+   * @param {!Launcher.ChromeArgOptions=} options
    * @return {!Array<string>}
    */
   defaultArgs(options = {}) {
@@ -274,7 +274,7 @@ class Launcher {
   }
 
   /**
-   * @param {!(BrowserOptions & {browserWSEndpoint: string, transport?: !Puppeteer.ConnectionTransport})} options
+   * @param {!(Launcher.BrowserOptions & {browserWSEndpoint: string, transport?: !Puppeteer.ConnectionTransport})} options
    * @return {!Promise<!Browser>}
    */
   async connect(options) {
@@ -374,7 +374,7 @@ function waitForWSEndpoint(chromeProcess, timeout, preferredRevision) {
 }
 
 /**
- * @typedef {Object} ChromeArgOptions
+ * @typedef {Object} Launcher.ChromeArgOptions
  * @property {boolean=} headless
  * @property {Array<string>=} args
  * @property {string=} userDataDir
@@ -382,9 +382,9 @@ function waitForWSEndpoint(chromeProcess, timeout, preferredRevision) {
  */
 
 /**
- * @typedef {Object} LaunchOptions
+ * @typedef {Object} Launcher.LaunchOptions
  * @property {string=} executablePath
- * @property {boolean=} ignoreDefaultArgs
+ * @property {boolean|Array<string>=} ignoreDefaultArgs
  * @property {boolean=} handleSIGINT
  * @property {boolean=} handleSIGTERM
  * @property {boolean=} handleSIGHUP
@@ -395,7 +395,7 @@ function waitForWSEndpoint(chromeProcess, timeout, preferredRevision) {
  */
 
 /**
- * @typedef {Object} BrowserOptions
+ * @typedef {Object} Launcher.BrowserOptions
  * @property {boolean=} ignoreHTTPSErrors
  * @property {(?Puppeteer.Viewport)=} defaultViewport
  * @property {number=} slowMo

lib/NetworkManager.js

@@ -391,18 +391,24 @@ class Request {
   }
 
   /**
-   * @param {!Object=} overrides
+   * @param {!{url?: string, method?:string, postData?: string, headers?: !Object}} overrides
    */
   async continue(overrides = {}) {
     assert(this._allowInterception, 'Request Interception is not enabled!');
     assert(!this._interceptionHandled, 'Request is already handled!');
+    const {
+      url,
+      method,
+      postData,
+      headers
+    } = overrides;
     this._interceptionHandled = true;
     await this._client.send('Network.continueInterceptedRequest', {
       interceptionId: this._interceptionId,
-      url: overrides.url,
+      url,
-      method: overrides.method,
+      method,
-      postData: overrides.postData,
+      postData,
-      headers: overrides.headers,
+      headers,
     }).catch(error => {
       // In certain cases, protocol will return error if the request was already canceled
       // or the page was closed. We should tolerate these errors.

lib/Page.js

@@ -350,7 +350,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {Array<Network.CookieParam>} cookies
+   * @param {Array<Protocol.Network.deleteCookiesParameters>} cookies
    */
   async deleteCookie(...cookies) {
     const pageURL = this.url();
@@ -388,7 +388,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {Object} options
+   * @param {!{url?: string, path?: string, content?: string, type?: string}} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   async addScriptTag(options) {
@@ -396,7 +396,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {Object} options
+   * @param {!{url?: string, path?: string, content?: string}} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   async addStyleTag(options) {
@@ -457,7 +457,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @return {!Promise<!Object>}
+   * @return {!Promise<!Metrics>}
    */
   async metrics() {
     const response = await this._client.send('Performance.getMetrics');
@@ -465,7 +465,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {*} event
+   * @param {!Protocol.Performance.metricsPayload} event
    */
   _emitMetrics(event) {
     this.emit(Page.Events.Metrics, {
@@ -476,7 +476,7 @@ class Page extends EventEmitter {
 
   /**
    * @param {?Array<!Protocol.Performance.Metric>} metrics
-   * @return {!Object}
+   * @return {!Metrics}
    */
   _buildMetricsObject(metrics) {
     const result = {};
@@ -580,15 +580,15 @@ class Page extends EventEmitter {
 
   /**
    * @param {string} url
-   * @param {!Object=} options
+   * @param {!{referer?: string, timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
-  async goto(url, options = {}) {
+  async goto(url, options) {
     return await this._frameManager.mainFrame().goto(url, options);
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
   async reload(options) {
@@ -600,7 +600,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
   async waitForNavigation(options = {}) {
@@ -609,11 +609,13 @@ class Page extends EventEmitter {
 
   /**
    * @param {(string|Function)} urlOrPredicate
-   * @param {!Object=} options
+   * @param {!{timeout?: number}=} options
    * @return {!Promise<!Puppeteer.Request>}
    */
   async waitForRequest(urlOrPredicate, options = {}) {
-    const timeout = typeof options.timeout === 'number' ? options.timeout : 30000;
+    const {
+      timeout = 30000
+    } = options;
     return helper.waitForEvent(this._networkManager, NetworkManager.Events.Request, request => {
       if (helper.isString(urlOrPredicate))
         return (urlOrPredicate === request.url());
@@ -625,11 +627,13 @@ class Page extends EventEmitter {
 
   /**
    * @param {(string|Function)} urlOrPredicate
-   * @param {!Object=} options
+   * @param {!{timeout?: number}=} options
    * @return {!Promise<!Puppeteer.Response>}
    */
   async waitForResponse(urlOrPredicate, options = {}) {
-    const timeout = typeof options.timeout === 'number' ? options.timeout : 30000;
+    const {
+      timeout = 30000
+    } = options;
     return helper.waitForEvent(this._networkManager, NetworkManager.Events.Response, response => {
       if (helper.isString(urlOrPredicate))
         return (urlOrPredicate === response.url());
@@ -640,7 +644,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
   async goBack(options) {
@@ -648,7 +652,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
   async goForward(options) {
@@ -656,7 +660,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!{timeout?: number, waitUntil?: string|!Array<string>}=} options
    * @return {!Promise<?Puppeteer.Response>}
    */
   async _go(delta, options) {
@@ -676,7 +680,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {!Object} options
+   * @param {!{viewport: !Puppeteer.Viewport, userAgent: string}} options
    */
   async emulate(options) {
     await Promise.all([
@@ -753,7 +757,7 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!ScreenshotOptions=} options
    * @return {!Promise<!Buffer|!String>}
    */
   async screenshot(options = {}) {
@@ -793,14 +797,12 @@ class Page extends EventEmitter {
 
   /**
    * @param {"png"|"jpeg"} format
-   * @param {!Object=} options
+   * @param {!ScreenshotOptions=} options
    * @return {!Promise<!Buffer|!String>}
    */
   async _screenshotTask(format, options) {
     await this._client.send('Target.activateTarget', {targetId: this._target._targetId});
-    let clip = options.clip ? Object.assign({}, options['clip']) : undefined;
+    let clip = options.clip ? Object.assign({}, options['clip'], {scale: 1}) : undefined;
-    if (clip)
-      clip.scale = 1;
 
     if (options.fullPage) {
       const metrics = await this._client.send('Page.getLayoutMetrics');
@@ -835,17 +837,22 @@ class Page extends EventEmitter {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!PDFOptions=} options
    * @return {!Promise<!Buffer>}
    */
   async pdf(options = {}) {
-    const scale = options.scale || 1;
+    const {
-    const displayHeaderFooter = !!options.displayHeaderFooter;
+      scale = 1,
-    const headerTemplate = options.headerTemplate || '';
+      displayHeaderFooter = false,
-    const footerTemplate = options.footerTemplate || '';
+      headerTemplate = '',
-    const printBackground = !!options.printBackground;
+      footerTemplate = '',
-    const landscape = !!options.landscape;
+      printBackground = false,
-    const pageRanges = options.pageRanges || '';
+      landscape = false,
+      pageRanges = '',
+      preferCSSPageSize = false,
+      margin = {},
+      path = null
+    } = options;
 
     let paperWidth = 8.5;
     let paperHeight = 11;
@@ -859,32 +866,30 @@ class Page extends EventEmitter {
       paperHeight = convertPrintParameterToInches(options.height) || paperHeight;
     }
 
-    const marginOptions = options.margin || {};
+    const marginTop = convertPrintParameterToInches(margin.top) || 0;
-    const marginTop = convertPrintParameterToInches(marginOptions.top) || 0;
+    const marginLeft = convertPrintParameterToInches(margin.left) || 0;
-    const marginLeft = convertPrintParameterToInches(marginOptions.left) || 0;
+    const marginBottom = convertPrintParameterToInches(margin.bottom) || 0;
-    const marginBottom = convertPrintParameterToInches(marginOptions.bottom) || 0;
+    const marginRight = convertPrintParameterToInches(margin.right) || 0;
-    const marginRight = convertPrintParameterToInches(marginOptions.right) || 0;
-    const preferCSSPageSize = options.preferCSSPageSize || false;
 
     const result = await this._client.send('Page.printToPDF', {
-      landscape: landscape,
+      landscape,
-      displayHeaderFooter: displayHeaderFooter,
+      displayHeaderFooter,
-      headerTemplate: headerTemplate,
+      headerTemplate,
-      footerTemplate: footerTemplate,
+      footerTemplate,
-      printBackground: printBackground,
+      printBackground,
-      scale: scale,
+      scale,
-      paperWidth: paperWidth,
+      paperWidth,
-      paperHeight: paperHeight,
+      paperHeight,
-      marginTop: marginTop,
+      marginTop,
-      marginBottom: marginBottom,
+      marginBottom,
-      marginLeft: marginLeft,
+      marginLeft,
-      marginRight: marginRight,
+      marginRight,
-      pageRanges: pageRanges,
+      pageRanges,
-      preferCSSPageSize: preferCSSPageSize
+      preferCSSPageSize
     });
     const buffer = Buffer.from(result.data, 'base64');
-    if (options.path)
+    if (path !== null)
-      await writeFileAsync(options.path, buffer);
+      await writeFileAsync(path, buffer);
     return buffer;
   }
 
@@ -925,7 +930,7 @@ class Page extends EventEmitter {
 
   /**
    * @param {string} selector
-   * @param {!Object=} options
+   * @param {!{delay?: number, button?: "left"|"right"|"middle", clickCount?: number}=} options
    */
   click(selector, options = {}) {
     return this.mainFrame().click(selector, options);
@@ -982,7 +987,7 @@ class Page extends EventEmitter {
 
   /**
    * @param {string} selector
-   * @param {!Object=} options
+   * @param {!{visible?: boolean, hidden?: boolean, timeout?: number}=} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   waitForSelector(selector, options = {}) {
@@ -991,7 +996,7 @@ class Page extends EventEmitter {
 
   /**
    * @param {string} xpath
-   * @param {!Object=} options
+   * @param {!{visible?: boolean, hidden?: boolean, timeout?: number}=} options
    * @return {!Promise<!Puppeteer.ElementHandle>}
    */
   waitForXPath(xpath, options = {}) {
@@ -1000,7 +1005,7 @@ class Page extends EventEmitter {
 
   /**
    * @param {function()} pageFunction
-   * @param {!Object=} options
+   * @param {!{polling?: string|number, timeout?: number}=} options
    * @param {!Array<*>} args
    * @return {!Promise<!Puppeteer.JSHandle>}
    */
@@ -1009,6 +1014,51 @@ class Page extends EventEmitter {
   }
 }
 
+/**
+ * @typedef {Object} PDFOptions
+ * @property {number=} scale
+ * @property {boolean=} displayHeaderFooter
+ * @property {string=} headerTemplate
+ * @property {string=} footerTemplate
+ * @property {boolean=} printBackground
+ * @property {boolean=} landscape
+ * @property {string=} pageRanges
+ * @property {string=} format
+ * @property {string|number=} width
+ * @property {string|number=} height
+ * @property {boolean=} preferCSSPageSize
+ * @property {!{top?: string|number, bottom?: string|number, left?: string|number, right?: string|number}=} margin
+ * @property {string=} path
+ */
+
+/**
+ * @typedef {Object} Metrics
+ * @property {number=} Timestamp
+ * @property {number=} Documents
+ * @property {number=} Frames
+ * @property {number=} JSEventListeners
+ * @property {number=} Nodes
+ * @property {number=} LayoutCount
+ * @property {number=} RecalcStyleCount
+ * @property {number=} LayoutDuration
+ * @property {number=} RecalcStyleDuration
+ * @property {number=} ScriptDuration
+ * @property {number=} TaskDuration
+ * @property {number=} JSHeapUsedSize
+ * @property {number=} JSHeapTotalSize
+ */
+
+/**
+ * @typedef {Object} ScreenshotOptions
+ * @property {string=} type
+ * @property {string=} path
+ * @property {boolean=} fullPage
+ * @property {{x: number, y: number, width: number, height: number}=} clip
+ * @property {number=} quality
+ * @property {boolean=} omitBackground
+ * @property {string=} encoding
+ */
+
 /** @type {!Set<string>} */
 const supportedMetrics = new Set([
   'Timestamp',

lib/Puppeteer.js

@@ -29,7 +29,7 @@ module.exports = class {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!(Launcher.LaunchOptions & Launcher.ChromeArgOptions & Launcher.BrowserOptions)=} options
    * @return {!Promise<!Puppeteer.Browser>}
    */
   launch(options) {
@@ -37,7 +37,7 @@ module.exports = class {
   }
 
   /**
-   * @param {{browserWSEndpoint: string, ignoreHTTPSErrors: boolean, transport?: !Puppeteer.ConnectionTransport}} options
+   * @param {!(Launcher.BrowserOptions & {browserWSEndpoint: string, transport?: !Puppeteer.ConnectionTransport})} options
    * @return {!Promise<!Puppeteer.Browser>}
    */
   connect(options) {
@@ -52,6 +52,7 @@ module.exports = class {
   }
 
   /**
+   * @param {!Launcher.ChromeArgOptions=} options
    * @return {!Array<string>}
    */
   defaultArgs(options) {
@@ -59,7 +60,7 @@ module.exports = class {
   }
 
   /**
-   * @param {!Object=} options
+   * @param {!BrowserFetcher.Options=} options
    * @return {!BrowserFetcher}
    */
   createBrowserFetcher(options) {

lib/Tracing.js

@@ -31,7 +31,7 @@ class Tracing {
   }
 
   /**
-   * @param {!Object} options
+   * @param {!{path: string, screenshots?: boolean, categories?: !Array<string>}} options
    */
   async start(options) {
     assert(!this._recording, 'Cannot start recording trace while already recording trace.');
@@ -42,16 +42,20 @@ class Tracing {
       'blink.console', 'blink.user_timing', 'latencyInfo', 'disabled-by-default-devtools.timeline.stack',
       'disabled-by-default-v8.cpu_profiler', 'disabled-by-default-v8.cpu_profiler.hires'
     ];
-    const categoriesArray = options.categories || defaultCategories;
+    const {
+      path = null,
+      screenshots = false,
+      categories = defaultCategories,
+    } = options;
 
-    if (options.screenshots)
+    if (screenshots)
-      categoriesArray.push('disabled-by-default-devtools.screenshot');
+      categories.push('disabled-by-default-devtools.screenshot');
 
-    this._path = options.path;
+    this._path = path;
     this._recording = true;
     await this._client.send('Tracing.start', {
       transferMode: 'ReturnAsStream',
-      categories: categoriesArray.join(',')
+      categories: categories.join(',')
     });
   }