diff --git a/docs/api.md b/docs/api.md
index ceffda08236..4eee3fb791e 100644
--- a/docs/api.md
+++ b/docs/api.md
@@ -97,35 +97,35 @@
   * [page.bringToFront()](#pagebringtofront)
   * [page.browser()](#pagebrowser)
   * [page.click(selector[, options])](#pageclickselector-options)
-  * [page.close(options)](#pagecloseoptions)
+  * [page.close([options])](#pagecloseoptions)
   * [page.content()](#pagecontent)
-  * [page.cookies(...urls)](#pagecookiesurls)
+  * [page.cookies([...urls])](#pagecookiesurls)
   * [page.coverage](#pagecoverage)
   * [page.deleteCookie(...cookies)](#pagedeletecookiecookies)
   * [page.emulate(options)](#pageemulateoptions)
   * [page.emulateMedia(mediaType)](#pageemulatemediamediatype)
-  * [page.evaluate(pageFunction, ...args)](#pageevaluatepagefunction-args)
-  * [page.evaluateHandle(pageFunction, ...args)](#pageevaluatehandlepagefunction-args)
-  * [page.evaluateOnNewDocument(pageFunction, ...args)](#pageevaluateonnewdocumentpagefunction-args)
+  * [page.evaluate(pageFunction[, ...args])](#pageevaluatepagefunction-args)
+  * [page.evaluateHandle(pageFunction[, ...args])](#pageevaluatehandlepagefunction-args)
+  * [page.evaluateOnNewDocument(pageFunction[, ...args])](#pageevaluateonnewdocumentpagefunction-args)
   * [page.exposeFunction(name, puppeteerFunction)](#pageexposefunctionname-puppeteerfunction)
   * [page.focus(selector)](#pagefocusselector)
   * [page.frames()](#pageframes)
-  * [page.goBack(options)](#pagegobackoptions)
-  * [page.goForward(options)](#pagegoforwardoptions)
-  * [page.goto(url, options)](#pagegotourl-options)
+  * [page.goBack([options])](#pagegobackoptions)
+  * [page.goForward([options])](#pagegoforwardoptions)
+  * [page.goto(url[, options])](#pagegotourl-options)
   * [page.hover(selector)](#pagehoverselector)
   * [page.isClosed()](#pageisclosed)
   * [page.keyboard](#pagekeyboard)
   * [page.mainFrame()](#pagemainframe)
   * [page.metrics()](#pagemetrics)
   * [page.mouse](#pagemouse)
-  * [page.pdf(options)](#pagepdfoptions)
+  * [page.pdf([options])](#pagepdfoptions)
   * [page.queryObjects(prototypeHandle)](#pagequeryobjectsprototypehandle)
-  * [page.reload(options)](#pagereloadoptions)
+  * [page.reload([options])](#pagereloadoptions)
   * [page.screenshot([options])](#pagescreenshotoptions)
   * [page.select(selector, ...values)](#pageselectselector-values)
   * [page.setBypassCSP(enabled)](#pagesetbypasscspenabled)
-  * [page.setCacheEnabled(enabled)](#pagesetcacheenabledenabled)
+  * [page.setCacheEnabled([enabled])](#pagesetcacheenabledenabled)
   * [page.setContent(html)](#pagesetcontenthtml)
   * [page.setCookie(...cookies)](#pagesetcookiecookies)
   * [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout)
@@ -146,15 +146,15 @@
   * [page.viewport()](#pageviewport)
   * [page.waitFor(selectorOrFunctionOrTimeout[, options[, ...args]])](#pagewaitforselectororfunctionortimeout-options-args)
   * [page.waitForFunction(pageFunction[, options[, ...args]])](#pagewaitforfunctionpagefunction-options-args)
-  * [page.waitForNavigation(options)](#pagewaitfornavigationoptions)
-  * [page.waitForRequest(urlOrPredicate, options)](#pagewaitforrequesturlorpredicate-options)
-  * [page.waitForResponse(urlOrPredicate, options)](#pagewaitforresponseurlorpredicate-options)
+  * [page.waitForNavigation([options])](#pagewaitfornavigationoptions)
+  * [page.waitForRequest(urlOrPredicate[, options])](#pagewaitforrequesturlorpredicate-options)
+  * [page.waitForResponse(urlOrPredicate[, options])](#pagewaitforresponseurlorpredicate-options)
   * [page.waitForSelector(selector[, options])](#pagewaitforselectorselector-options)
   * [page.waitForXPath(xpath[, options])](#pagewaitforxpathxpath-options)
   * [page.workers()](#pageworkers)
 - [class: Worker](#class-worker)
-  * [worker.evaluate(pageFunction, ...args)](#workerevaluatepagefunction-args)
-  * [worker.evaluateHandle(pageFunction, ...args)](#workerevaluatehandlepagefunction-args)
+  * [worker.evaluate(pageFunction[, ...args])](#workerevaluatepagefunction-args)
+  * [worker.evaluateHandle(pageFunction[, ...args])](#workerevaluatehandlepagefunction-args)
   * [worker.executionContext()](#workerexecutioncontext)
   * [worker.url()](#workerurl)
 - [class: Accessibility](#class-accessibility)
@@ -163,12 +163,12 @@
   * [keyboard.down(key[, options])](#keyboarddownkey-options)
   * [keyboard.press(key[, options])](#keyboardpresskey-options)
   * [keyboard.sendCharacter(char)](#keyboardsendcharacterchar)
-  * [keyboard.type(text, options)](#keyboardtypetext-options)
+  * [keyboard.type(text[, options])](#keyboardtypetext-options)
   * [keyboard.up(key)](#keyboardupkey)
 - [class: Mouse](#class-mouse)
-  * [mouse.click(x, y, [options])](#mouseclickx-y-options)
+  * [mouse.click(x, y[, options])](#mouseclickx-y-options)
   * [mouse.down([options])](#mousedownoptions)
-  * [mouse.move(x, y, [options])](#mousemovex-y-options)
+  * [mouse.move(x, y[, options])](#mousemovex-y-options)
   * [mouse.up([options])](#mouseupoptions)
 - [class: Touchscreen](#class-touchscreen)
   * [touchscreen.tap(x, y)](#touchscreentapx-y)
@@ -196,11 +196,11 @@
   * [frame.childFrames()](#framechildframes)
   * [frame.click(selector[, options])](#frameclickselector-options)
   * [frame.content()](#framecontent)
-  * [frame.evaluate(pageFunction, ...args)](#frameevaluatepagefunction-args)
-  * [frame.evaluateHandle(pageFunction, ...args)](#frameevaluatehandlepagefunction-args)
+  * [frame.evaluate(pageFunction[, ...args])](#frameevaluatepagefunction-args)
+  * [frame.evaluateHandle(pageFunction[, ...args])](#frameevaluatehandlepagefunction-args)
   * [frame.executionContext()](#frameexecutioncontext)
   * [frame.focus(selector)](#framefocusselector)
-  * [frame.goto(url, options)](#framegotourl-options)
+  * [frame.goto(url[, options])](#framegotourl-options)
   * [frame.hover(selector)](#framehoverselector)
   * [frame.isDetached()](#frameisdetached)
   * [frame.name()](#framename)
@@ -213,12 +213,12 @@
   * [frame.url()](#frameurl)
   * [frame.waitFor(selectorOrFunctionOrTimeout[, options[, ...args]])](#framewaitforselectororfunctionortimeout-options-args)
   * [frame.waitForFunction(pageFunction[, options[, ...args]])](#framewaitforfunctionpagefunction-options-args)
-  * [frame.waitForNavigation(options)](#framewaitfornavigationoptions)
+  * [frame.waitForNavigation([options])](#framewaitfornavigationoptions)
   * [frame.waitForSelector(selector[, options])](#framewaitforselectorselector-options)
   * [frame.waitForXPath(xpath[, options])](#framewaitforxpathxpath-options)
 - [class: ExecutionContext](#class-executioncontext)
-  * [executionContext.evaluate(pageFunction, ...args)](#executioncontextevaluatepagefunction-args)
-  * [executionContext.evaluateHandle(pageFunction, ...args)](#executioncontextevaluatehandlepagefunction-args)
+  * [executionContext.evaluate(pageFunction[, ...args])](#executioncontextevaluatepagefunction-args)
+  * [executionContext.evaluateHandle(pageFunction[, ...args])](#executioncontextevaluatehandlepagefunction-args)
   * [executionContext.frame()](#executioncontextframe)
   * [executionContext.queryObjects(prototypeHandle)](#executioncontextqueryobjectsprototypehandle)
 - [class: JSHandle](#class-jshandle)
@@ -231,8 +231,8 @@
 - [class: ElementHandle](#class-elementhandle)
   * [elementHandle.$(selector)](#elementhandleselector)
   * [elementHandle.$$(selector)](#elementhandleselector-1)
-  * [elementHandle.$$eval(selector, pageFunction, ...args)](#elementhandleevalselector-pagefunction-args)
-  * [elementHandle.$eval(selector, pageFunction, ...args)](#elementhandleevalselector-pagefunction-args-1)
+  * [elementHandle.$$eval(selector, pageFunction[, ...args])](#elementhandleevalselector-pagefunction-args)
+  * [elementHandle.$eval(selector, pageFunction[, ...args])](#elementhandleevalselector-pagefunction-args-1)
   * [elementHandle.$x(expression)](#elementhandlexexpression)
   * [elementHandle.asElement()](#elementhandleaselement)
   * [elementHandle.boundingBox()](#elementhandleboundingbox)
@@ -300,8 +300,8 @@
   * [cdpSession.detach()](#cdpsessiondetach)
   * [cdpSession.send(method[, params])](#cdpsessionsendmethod-params)
 - [class: Coverage](#class-coverage)
-  * [coverage.startCSSCoverage(options)](#coveragestartcsscoverageoptions)
-  * [coverage.startJSCoverage(options)](#coveragestartjscoverageoptions)
+  * [coverage.startCSSCoverage([options])](#coveragestartcsscoverageoptions)
+  * [coverage.startJSCoverage([options])](#coveragestartjscoverageoptions)
   * [coverage.stopCSSCoverage()](#coveragestopcsscoverage)
   * [coverage.stopJSCoverage()](#coveragestopjscoverage)
 - [class: TimeoutError](#class-timeouterror)
@@ -1121,7 +1121,7 @@ const [response] = await Promise.all([
 
 Shortcut for [page.mainFrame().click(selector[, options])](#frameclickselector-options).
 
-#### page.close(options)
+#### page.close([options])
 - `options` <[Object]>
   - `runBeforeUnload` <[boolean]> Defaults to `false`. Whether to run the
     [before unload](https://developer.mozilla.org/en-US/docs/Web/Events/beforeunload)
@@ -1138,7 +1138,7 @@ By default, `page.close()` **does not** run beforeunload handlers.
 
 Gets the full HTML contents of the page, including the doctype.
 
-#### page.cookies(...urls)
+#### page.cookies([...urls])
 - `...urls` <...[string]>
 - returns: <[Promise]<[Array]<[Object]>>>
   - `name` <[string]>
@@ -1205,7 +1205,7 @@ List of all available devices is available in the source code: [DeviceDescriptor
 - `mediaType` <?[string]> Changes the CSS media type of the page. The only allowed values are `'screen'`, `'print'` and `null`. Passing `null` disables media emulation.
 - returns: <[Promise]>
 
-#### page.evaluate(pageFunction, ...args)
+#### page.evaluate(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in the page context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
 - returns: <[Promise]<[Serializable]>> Promise which resolves to the return value of `pageFunction`
@@ -1238,7 +1238,7 @@ await bodyHandle.dispose();
 
 Shortcut for [page.mainFrame().evaluate(pageFunction, ...args)](#frameevaluatepagefunction-args).
 
-#### page.evaluateHandle(pageFunction, ...args)
+#### page.evaluateHandle(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in the page context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
 - returns: <[Promise]<[JSHandle]>> Promise which resolves to the return value of `pageFunction` as in-page object (JSHandle)
@@ -1262,7 +1262,7 @@ await resultHandle.dispose();
 
 Shortcut for [page.mainFrame().executionContext().evaluateHandle(pageFunction, ...args)](#executioncontextevaluatehandlepagefunction-args).
 
-#### page.evaluateOnNewDocument(pageFunction, ...args)
+#### page.evaluateOnNewDocument(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in browser context
 - `...args` <...[Serializable]> Arguments to pass to `pageFunction`
 - returns: <[Promise]>
@@ -1364,7 +1364,7 @@ Shortcut for [page.mainFrame().focus(selector)](#framefocusselector).
 #### page.frames()
 - returns: <[Array]<[Frame]>> An array of all frames attached to the page.
 
-#### page.goBack(options)
+#### page.goBack([options])
 - `options` <[Object]> Navigation parameters which might have the following properties:
   - `timeout` <[number]> Maximum navigation time in milliseconds, defaults to 30 seconds, pass `0` to disable timeout. The default value can be changed by using the [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout) method.
   - `waitUntil` <[string]|[Array]<[string]>> When to consider navigation succeeded, defaults to `load`. Given an array of event strings, navigation is considered to be successful after all events have been fired. Events can be either:
@@ -1377,7 +1377,7 @@ can not go back, resolves to `null`.
 
 Navigate to the previous page in history.
 
-#### page.goForward(options)
+#### page.goForward([options])
 - `options` <[Object]> Navigation parameters which might have the following properties:
   - `timeout` <[number]> Maximum navigation time in milliseconds, defaults to 30 seconds, pass `0` to disable timeout. The default value can be changed by using the [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout) method.
   - `waitUntil` <[string]|[Array]<[string]>> When to consider navigation succeeded, defaults to `load`. Given an array of event strings, navigation is considered to be successful after all events have been fired. Events can be either:
@@ -1390,7 +1390,7 @@ can not go forward, resolves to `null`.
 
 Navigate to the next page in history.
 
-#### page.goto(url, options)
+#### page.goto(url[, options])
 - `url` <[string]> URL to navigate page to. The url should include scheme, e.g. `https://`.
 - `options` <[Object]> Navigation parameters which might have the following properties:
   - `timeout` <[number]> Maximum navigation time in milliseconds, defaults to 30 seconds, pass `0` to disable timeout. The default value can be changed by using the [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout) method.
@@ -1460,7 +1460,7 @@ Page is guaranteed to have a main frame which persists during navigations.
 
 - returns: <[Mouse]>
 
-#### page.pdf(options)
+#### page.pdf([options])
 - `options` <[Object]> Options object which might have the following properties:
   - `path` <[string]> The file path to save the PDF to. If `path` is a relative path, then it is resolved relative to [current working directory](https://nodejs.org/api/process.html#process_process_cwd). If no path is provided, the PDF won't be saved to the disk.
   - `scale` <[number]> Scale of the webpage rendering. Defaults to `1`. Scale amount must be between 0.1 and 2.
@@ -1549,7 +1549,7 @@ await mapPrototype.dispose();
 
 Shortcut for [page.mainFrame().executionContext().queryObjects(prototypeHandle)](#executioncontextqueryobjectsprototypehandle).
 
-#### page.reload(options)
+#### page.reload([options])
 - `options` <[Object]> Navigation parameters which might have the following properties:
   - `timeout` <[number]> Maximum navigation time in milliseconds, defaults to 30 seconds, pass `0` to disable timeout. The default value can be changed by using the [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout) method.
   - `waitUntil` <[string]|[Array]<[string]>> When to consider navigation succeeded, defaults to `load`. Given an array of event strings, navigation is considered to be successful after all events have been fired. Events can be either:
@@ -1600,7 +1600,7 @@ Toggles bypassing page's Content-Security-Policy.
 > **NOTE** CSP bypassing happens at the moment of CSP initialization rather then evaluation. Usually this means
 that `page.setBypassCSP` should be called before navigating to the domain.
 
-#### page.setCacheEnabled(enabled)
+#### page.setCacheEnabled([enabled])
 - `enabled` <[boolean]> sets the `enabled` state of the cache.
 - returns: <[Promise]>
 
@@ -1631,11 +1631,11 @@ await page.setCookie(cookieObject1, cookieObject2);
 - `timeout` <[number]> Maximum navigation time in milliseconds
 
 This setting will change the default maximum navigation time of 30 seconds for the following methods:
-- [page.goto(url, options)](#pagegotourl-options)
-- [page.goBack(options)](#pagegobackoptions)
-- [page.goForward(options)](#pagegoforwardoptions)
-- [page.reload(options)](#pagereloadoptions)
-- [page.waitForNavigation(options)](#pagewaitfornavigationoptions)
+- [page.goto(url[, options])](#pagegotourl-options)
+- [page.goBack([options])](#pagegobackoptions)
+- [page.goForward([options])](#pagegoforwardoptions)
+- [page.reload([options])](#pagereloadoptions)
+- [page.waitForNavigation([options])](#pagewaitfornavigationoptions)
 
 #### page.setExtraHTTPHeaders(headers)
 - `headers` <[Object]> An object containing additional HTTP headers to be sent with every request. All header values must be strings.
@@ -1835,7 +1835,7 @@ await page.waitForFunction(selector => !!document.querySelector(selector), {}, s
 
 Shortcut for [page.mainFrame().waitForFunction(pageFunction[, options[, ...args]])](#framewaitforfunctionpagefunction-options-args).
 
-#### page.waitForNavigation(options)
+#### page.waitForNavigation([options])
 - `options` <[Object]> Navigation parameters which might have the following properties:
   - `timeout` <[number]> Maximum navigation time in milliseconds, defaults to 30 seconds, pass `0` to disable timeout. The default value can be changed by using the [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout) method.
   - `waitUntil` <[string]|[Array]<[string]>> When to consider navigation succeeded, defaults to `load`. Given an array of event strings, navigation is considered to be successful after all events have been fired. Events can be either:
@@ -1859,7 +1859,7 @@ const [response] = await Promise.all([
 
 Shortcut for [page.mainFrame().waitForNavigation(options)](#framewaitfornavigationoptions).
 
-#### page.waitForRequest(urlOrPredicate, options)
+#### page.waitForRequest(urlOrPredicate[, options])
 - `urlOrPredicate` <[string]|[Function]> A URL or predicate to wait for.
 - `options` <[Object]> Optional waiting parameters
   - `timeout` <[number]> Maximum wait time in milliseconds, defaults to 30 seconds, pass `0` to disable the timeout.
@@ -1871,7 +1871,7 @@ const finalRequest = await page.waitForRequest(request => request.url() === 'htt
 return firstRequest.url();
 ```
 
-#### page.waitForResponse(urlOrPredicate, options)
+#### page.waitForResponse(urlOrPredicate[, options])
 - `urlOrPredicate` <[string]|[Function]> A URL or predicate to wait for.
 - `options` <[Object]> Optional waiting parameters
   - `timeout` <[number]> Maximum wait time in milliseconds, defaults to 30 seconds, pass `0` to disable the timeout.
@@ -1961,7 +1961,7 @@ for (const worker of page.workers())
   console.log('  ' + worker.url());
 ```
 
-#### worker.evaluate(pageFunction, ...args)
+#### worker.evaluate(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in the worker context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
 - returns: <[Promise]<[Serializable]>> Promise which resolves to the return value of `pageFunction`
@@ -1972,7 +1972,7 @@ If the function passed to the `worker.evaluate` returns a non-[Serializable] val
 
 Shortcut for [(await worker.executionContext()).evaluate(pageFunction, ...args)](#executioncontextevaluatepagefunction-args).
 
-#### worker.evaluateHandle(pageFunction, ...args)
+#### worker.evaluateHandle(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in the page context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
 - returns: <[Promise]<[JSHandle]>> Promise which resolves to the return value of `pageFunction` as in-page object (JSHandle)
@@ -2132,7 +2132,7 @@ page.keyboard.sendCharacter('嗨');
 
 > **NOTE** Modifier keys DO NOT effect `keyboard.sendCharacter`. Holding down `Shift` will not type the text in upper case.
 
-#### keyboard.type(text, options)
+#### keyboard.type(text[, options])
 - `text` <[string]> A text to type into a focused element.
 - `options` <[Object]>
   - `delay` <[number]> Time to wait between key presses in milliseconds. Defaults to 0.
@@ -2172,7 +2172,7 @@ await page.mouse.move(0, 0);
 await page.mouse.up();
 ```
 
-#### mouse.click(x, y, [options])
+#### mouse.click(x, y[, options])
 - `x` <[number]>
 - `y` <[number]>
 - `options` <[Object]>
@@ -2191,7 +2191,7 @@ Shortcut for [`mouse.move`](#mousemovex-y-options), [`mouse.down`](#mousedownopt
 
 Dispatches a `mousedown` event.
 
-#### mouse.move(x, y, [options])
+#### mouse.move(x, y[, options])
 - `x` <[number]>
 - `y` <[number]>
 - `options` <[Object]>
@@ -2422,7 +2422,7 @@ const [response] = await Promise.all([
 
 Gets the full HTML contents of the frame, including the doctype.
 
-#### frame.evaluate(pageFunction, ...args)
+#### frame.evaluate(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in browser context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to  `pageFunction`
 - returns: <[Promise]<[Serializable]>> Promise which resolves to the return value of `pageFunction`
@@ -2451,7 +2451,7 @@ const html = await frame.evaluate(body => body.innerHTML, bodyHandle);
 await bodyHandle.dispose();
 ```
 
-#### frame.evaluateHandle(pageFunction, ...args)
+#### frame.evaluateHandle(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in the page context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
 - returns: <[Promise]<[JSHandle]>> Promise which resolves to the return value of `pageFunction` as in-page object (JSHandle)
@@ -2492,7 +2492,7 @@ Returns promise that resolves to the frame's default execution context.
 This method fetches an element with `selector` and focuses it.
 If there's no element matching `selector`, the method throws an error.
 
-#### frame.goto(url, options)
+#### frame.goto(url[, options])
 - `url` <[string]> URL to navigate frame to. The url should include scheme, e.g. `https://`.
 - `options` <[Object]> Navigation parameters which might have the following properties:
   - `timeout` <[number]> Maximum navigation time in milliseconds, defaults to 30 seconds, pass `0` to disable timeout. The default value can be changed by using the [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout) method.
@@ -2646,7 +2646,7 @@ const selector = '.foo';
 await page.waitForFunction(selector => !!document.querySelector(selector), {}, selector);
 ```
 
-#### frame.waitForNavigation(options)
+#### frame.waitForNavigation([options])
 - `options` <[Object]> Navigation parameters which might have the following properties:
   - `timeout` <[number]> Maximum navigation time in milliseconds, defaults to 30 seconds, pass `0` to disable timeout. The default value can be changed by using the [page.setDefaultNavigationTimeout(timeout)](#pagesetdefaultnavigationtimeouttimeout) method.
   - `waitUntil` <[string]|[Array]<[string]>> When to consider navigation succeeded, defaults to `load`. Given an array of event strings, navigation is considered to be successful after all events have been fired. Events can be either:
@@ -2734,7 +2734,7 @@ The class represents a context for JavaScript execution. A [Page] might have man
 
 Besides pages, execution contexts can be found in [workers](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API).
 
-#### executionContext.evaluate(pageFunction, ...args)
+#### executionContext.evaluate(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in `executionContext`
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
 - returns: <[Promise]<[Serializable]>> Promise which resolves to the return value of `pageFunction`
@@ -2763,7 +2763,7 @@ await twoHandle.dispose();
 console.log(result); // prints '3'.
 ```
 
-#### executionContext.evaluateHandle(pageFunction, ...args)
+#### executionContext.evaluateHandle(pageFunction[, ...args])
 - `pageFunction` <[function]|[string]> Function to be evaluated in the `executionContext`
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
 - returns: <[Promise]<[JSHandle]>> Promise which resolves to the return value of `pageFunction` as in-page object (JSHandle)
@@ -2908,7 +2908,7 @@ The method runs `element.querySelector` within the page. If no element matches t
 
 The method runs `element.querySelectorAll` within the page. If no elements match the selector, the return value resolves to `[]`.
 
-#### elementHandle.$$eval(selector, pageFunction, ...args)
+#### elementHandle.$$eval(selector, pageFunction[, ...args])
 - `selector` <[string]> A [selector] to query page for
 - `pageFunction` <[function]> Function to be evaluated in browser context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
@@ -2930,7 +2930,7 @@ const feedHandle = await page.$('.feed');
 expect(await feedHandle.$$eval('.tweet', nodes => nodes.map(n => n.innerText))).toEqual(['Hello!', 'Hi!']);
 ```
 
-#### elementHandle.$eval(selector, pageFunction, ...args)
+#### elementHandle.$eval(selector, pageFunction[, ...args])
 - `selector` <[string]> A [selector] to query page for
 - `pageFunction` <[function]> Function to be evaluated in browser context
 - `...args` <...[Serializable]|[JSHandle]> Arguments to pass to `pageFunction`
@@ -3446,12 +3446,12 @@ console.log(`Bytes used: ${usedBytes / totalBytes * 100}%`);
 _To output coverage in a form consumable by [Istanbul](https://github.com/istanbuljs),
   see [puppeteer-to-istanbul](https://github.com/istanbuljs/puppeteer-to-istanbul)._
 
-#### coverage.startCSSCoverage(options)
+#### coverage.startCSSCoverage([options])
 - `options` <[Object]>  Set of configurable options for coverage
   - `resetOnNavigation` <[boolean]> Whether to reset coverage on every navigation. Defaults to `true`.
 - returns: <[Promise]> Promise that resolves when coverage is started
 
-#### coverage.startJSCoverage(options)
+#### coverage.startJSCoverage([options])
 - `options` <[Object]>  Set of configurable options for coverage
   - `resetOnNavigation` <[boolean]> Whether to reset coverage on every navigation. Defaults to `true`.
   - `reportAnonymousScripts` <[boolean]> Whether anonymous scripts generated by the page should be reported. Defaults to `false`.