class:worker · Puppeteer 中文文檔

# class:worker ### class: Worker v0.9.0 Worker 類表示一個 [WebWorker](https://developer.mozilla.org/en-US/docs/Web/API/Web_Workers_API)。在頁面對象上 `workercreated` 和 `workerdestroyed` 事件被觸發，以標識 worker 的生命周期。 ``` page.on('workercreated', worker => console.log('Worker created: ' + worker.url()));page.on('workerdestroyed', worker => console.log('Worker destroyed: ' + worker.url()));console.log('Current workers:');for (const worker of page.workers()) console.log(' ' + worker.url()); ``` #### Methods - [worker.evaluate(pageFunction, ...args)](#?product=Puppeteer&version=v1.11.0&show=api-workerevaluatepagefunction-args)v0.9.0 - [worker.evaluateHandle(pageFunction, ...args)](#?product=Puppeteer&version=v1.11.0&show=api-workerevaluatehandlepagefunction-args)v0.9.0 - [worker.executionContext()](#?product=Puppeteer&version=v1.11.0&show=api-workerexecutioncontext)v0.9.0 - [worker.url()](#?product=Puppeteer&version=v1.11.0&show=api-workerurl)v0.9.0 ### Methods #### worker.evaluate(pageFunction, ...args)v0.9.0 - `pageFunction` <[function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function "Function")|[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type "String")> Function to be evaluated in the worker context - `...args` <...[Serializable](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#Description "Serializable")|[JSHandle](#?product=Puppeteer&version=v1.11.0&show=api-class-jshandle "JSHandle")> Arguments to pass to `pageFunction` - returns: <[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise "Promise")<[Serializable](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#Description "Serializable")>> Promise which resolves to the return value of `pageFunction` 如果傳遞給 `worker.evaluate` 的函數返回一個 [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise "Promise")，那么 `worker.evaluate` 將等待解析并返回它的值。如果傳遞給 `worker.evaluate` 的函數返回一個非\[序列化\]的值，那么 `worker.evaluate` 解析為 `undefined`。 [(await worker.executionContext()).evaluate(pageFunction, ...args)](#?product=Puppeteer&version=v1.11.0&show=api-executioncontextevaluatepagefunction-args) 的快捷鏈接。 #### worker.evaluateHandle(pageFunction, ...args)v0.9.0 - `pageFunction` <[function](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Function "Function")|[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type "String")> Function to be evaluated in the page context - `...args` <...[Serializable](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/stringify#Description "Serializable")|[JSHandle](#?product=Puppeteer&version=v1.11.0&show=api-class-jshandle "JSHandle")> Arguments to pass to `pageFunction` - returns: <[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise "Promise")<[JSHandle](#?product=Puppeteer&version=v1.11.0&show=api-class-jshandle "JSHandle")>> Promise which resolves to the return value of `pageFunction` as in-page object (JSHandle) `worker.evaluate` 和 `worker.evaluateHandle` 之間的唯一區別是 `worker.evaluateHandle` 返回頁內對象（JSHandle）。如果傳遞給 `worker.evaluateHandle` 的函數返回一個 [Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise "Promise")，那么 `worker.evaluateHandle` 將等待解析并返回它的值。 [(await worker.executionContext()).evaluateHandle(pageFunction, ...args)](#?product=Puppeteer&version=v1.11.0&show=api-executioncontextevaluatehandlepagefunction-args) 的快捷鏈接。 #### worker.executionContext()v0.9.0 - returns: <[Promise](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Promise "Promise")<[ExecutionContext](#?product=Puppeteer&version=v1.11.0&show=api-class-executioncontext "ExecutionContext")>> #### worker.url()v0.9.0 - returns: <[string](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Data_structures#String_type "String")> ![](images/pptr.png) puppeteer.js中文網|class:worker puppeteer.js中文文檔, puppeteer chrome, puppeteer firefox, puppeteer api 中文文檔 puppeteer.js中文網包含了Puppeteer中文文檔，最新資訊，應用案例等。Puppeteer 是一個 Node 庫，它提供了一個高級 API 來通過 DevTools 協議控制 Chromium 或 Chrome。