puppeteer/assets/js/bcf29742.a9880144.js

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method",description:"Signature:",source:"@site/versioned_docs/version-16.1.0/api/puppeteer.page.evaluatehandle.md",sourceDirName:"api",slug:"/api/puppeteer.page.evaluatehandle",permalink:"/api/puppeteer.page.evaluatehandle",draft:!1,tags:[],version:"16.1.0",frontMatter:{sidebar_label:"Page.evaluateHandle"},sidebar:"sidebar",previous:{title:"Page.evaluate",permalink:"/api/puppeteer.page.evaluate"},next:{title:"Page.evaluateOnNewDocument",permalink:"/api/puppeteer.page.evaluateonnewdocument"}},u={},o=[{value:"Parameters",id:"parameters",level:2},{value:"Remarks",id:"remarks",level:2},{value:"Example 1",id:"example-1",level:2},{value:"Example 2",id:"example-2",level:2},{value:"Example 3",id:"example-3",level:2}],s={toc:o};function d(e){let{components:a,...t}=e;return(0,r.kt)("wrapper",(0,n.Z)({},s,t,{components:a,mdxType:"MDXLayout"}),(0,r.kt)("h1",{id:"pageevaluatehandle-method"},"Page.evaluateHandle() method"),(0,r.kt)("p",null,(0,r.kt)("strong",{parentName:"p"},"Signature:")),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-typescript"},"class Page {\n  evaluateHandle<\n    Params extends unknown[],\n    Func extends EvaluateFunc<Params> = EvaluateFunc<Params>\n  >(\n    pageFunction: Func | string,\n    ...args: Params\n  ): Promise<HandleFor<Awaited<ReturnType<Func>>>>;\n}\n")),(0,r.kt)("h2",{id:"parameters"},"Parameters"),(0,r.kt)("table",null,(0,r.kt)("thead",{parentName:"table"},(0,r.kt)("tr",{parentName:"thead"},(0,r.kt)("th",{parentName:"tr",align:null},"Parameter"),(0,r.kt)("th",{parentName:"tr",align:null},"Type"),(0,r.kt)("th",{parentName:"tr",align:null},"Description"))),(0,r.kt)("tbody",{parentName:"table"},(0,r.kt)("tr",{parentName:"tbody"},(0,r.kt)("td",{parentName:"tr",align:null},"pageFunction"),(0,r.kt)("td",{parentName:"tr",align:null},"Func ","|"," string"),(0,r.kt)("td",{parentName:"tr",align:null},"a function that is run within the page")),(0,r.kt)("tr",{parentName:"tbody"},(0,r.kt)("td",{parentName:"tr",align:null},"args"),(0,r.kt)("td",{parentName:"tr",align:null},"Params"),(0,r.kt)("td",{parentName:"tr",align:null},"arguments to be passed to the pageFunction")))),(0,r.kt)("p",null,(0,r.kt)("strong",{parentName:"p"},"Returns:")),(0,r.kt)("p",null,"Promise","<",(0,r.kt)("a",{parentName:"p",href:"/api/puppeteer.handlefor"},"HandleFor"),"<","Awaited","<","ReturnType","<","Func",">",">",">",">"),(0,r.kt)("h2",{id:"remarks"},"Remarks"),(0,r.kt)("p",null,"The only difference between ",(0,r.kt)("a",{parentName:"p",href:"/api/puppeteer.page.evaluate"},"page.evaluate")," and ",(0,r.kt)("inlineCode",{parentName:"p"},"page.evaluateHandle")," is that ",(0,r.kt)("inlineCode",{parentName:"p"},"evaluateHandle")," will return the value wrapped in an in-page object."),(0,r.kt)("p",null,"If the function passed to ",(0,r.kt)("inlineCode",{parentName:"p"},"page.evaluteHandle")," returns a Promise, the function will wait for the promise to resolve and return its value."),(0,r.kt)("p",null,"You can pass a string instead of a function (although functions are recommended as they are easier to debug and use with TypeScript):"),(0,r.kt)("h2",{id:"example-1"},"Example 1"),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-ts"},"const aHandle = await page.evaluateHandle('document');\n")),(0,r.kt)("h2",{id:"example-2"},"Example 2"),(0,r.kt)("p",null,(0,r.kt)("a",{parentName:"p",href:"/api/puppeteer.jshandle"},"JSHandle")," instances can be passed as arguments to the ",(0,r.kt)("inlineCode",{parentName:"p"},"pageFunction"),":"),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-ts"},"const aHandle = await page.evaluateHandle(() => document.body);\nconst resultHandle = await page.evaluateHandle(body => body.innerHTML, aHandle);\nconsole.log(await resultHandle.jsonValue());\nawait resultHandle.dispose();\n")),(0,r.kt)("p",null,"Most of the time this function returns a ",(0,r.kt)("a",{parentName:"p",href:"/api/puppeteer.jshandle"},"JSHandle"),", but if ",(0,r.kt)("inlineCode",{parentName:"p"},"pageFunction")," returns a reference to an element, you instead get an ",(0,r.kt)("a",{parentName:"p",href:"/api/puppeteer.elementhandle"},"ElementHandle")," back:"),(0,r.kt)("h2",{id:"example-3"},"Example 3"),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-ts"},"const button = await page.evaluateHandle(() =>\n  document.querySelector('button')\n);\n// can call `click` because `button` is an `ElementHandle`\nawait button.click();\n")),(0,r.kt)("p",null,"The TypeScript definitions assume that ",(0,r.kt)("inlineCode",{parentName:"p"},"evaluateHandle")," returns a ",(0,r.kt)("inlineCode",{parentName:"p"},"JSHandle"),", but if you know it's going to return an ",(0,r.kt)("inlineCode",{parentName:"p"},"ElementHandle"),", pass it as the generic argument:"),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-ts"},"const button = await page.evaluateHandle<ElementHandle>(...);\n")))}d.isMDXComponent=!0}}]);