puppeteer/assets/js/8ba52939.bccdc24a.js

/*! For license information please see 8ba52939.bccdc24a.js.LICENSE.txt */
"use strict";(self.webpackChunkwebsite=self.webpackChunkwebsite||[]).push([[2468],{79617:(e,n,a)=>{a.r(n),a.d(n,{assets:()=>c,contentTitle:()=>i,default:()=>o,frontMatter:()=>s,metadata:()=>l,toc:()=>d});var t=a(85893),r=a(11151);const s={sidebar_label:"Page.evaluate"},i="Page.evaluate() method",l={id:"api/puppeteer.page.evaluate",title:"Page.evaluate() method",description:"Evaluates a function in the page's context and returns the result.",source:"@site/versioned_docs/version-22.10.1/api/puppeteer.page.evaluate.md",sourceDirName:"api",slug:"/api/puppeteer.page.evaluate",permalink:"/api/puppeteer.page.evaluate",draft:!1,unlisted:!1,tags:[],version:"22.10.1",frontMatter:{sidebar_label:"Page.evaluate"},sidebar:"api",previous:{title:"Page.emulateVisionDeficiency",permalink:"/api/puppeteer.page.emulatevisiondeficiency"},next:{title:"Page.evaluateHandle",permalink:"/api/puppeteer.page.evaluatehandle"}},c={},d=[{value:"Signature:",id:"signature",level:4},{value:"Parameters",id:"parameters",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}];function p(e){const n={a:"a",code:"code",h1:"h1",h2:"h2",h4:"h4",p:"p",pre:"pre",strong:"strong",...(0,r.a)(),...e.components};return(0,t.jsxs)(t.Fragment,{children:[(0,t.jsx)(n.h1,{id:"pageevaluate-method",children:"Page.evaluate() method"}),"\n",(0,t.jsx)(n.p,{children:"Evaluates a function in the page's context and returns the result."}),"\n",(0,t.jsxs)(n.p,{children:["If the function passed to ",(0,t.jsx)(n.code,{children:"page.evaluate"})," returns a Promise, the function will wait for the promise to resolve and return its value."]}),"\n",(0,t.jsx)(n.h4,{id:"signature",children:"Signature:"}),"\n",(0,t.jsx)(n.pre,{children:(0,t.jsx)(n.code,{className:"language-typescript",children:"class Page {\n  evaluate<\n    Params extends unknown[],\n    Func extends EvaluateFunc<Params> = EvaluateFunc<Params>,\n  >(\n    pageFunction: Func | string,\n    ...args: Params\n  ): Promise<Awaited<ReturnType<Func>>>;\n}\n"})}),"\n",(0,t.jsx)(n.h2,{id:"parameters",children:"Parameters"}),"\n",(0,t.jsxs)("table",{children:[(0,t.jsx)("thead",{children:(0,t.jsxs)("tr",{children:[(0,t.jsx)("th",{children:(0,t.jsx)(n.p,{children:"Parameter"})}),(0,t.jsx)("th",{children:(0,t.jsx)(n.p,{children:"Type"})}),(0,t.jsx)("th",{children:(0,t.jsx)(n.p,{children:"Description"})})]})}),(0,t.jsxs)("tbody",{children:[(0,t.jsxs)("tr",{children:[(0,t.jsx)("td",{children:(0,t.jsx)(n.p,{children:"pageFunction"})}),(0,t.jsx)("td",{children:(0,t.jsx)(n.p,{children:"Func | string"})}),(0,t.jsx)("td",{children:(0,t.jsx)(n.p,{children:"a function that is run within the page"})})]}),(0,t.jsxs)("tr",{children:[(0,t.jsx)("td",{children:(0,t.jsx)(n.p,{children:"args"})}),(0,t.jsx)("td",{children:(0,t.jsx)(n.p,{children:"Params"})}),(0,t.jsx)("td",{children:(0,t.jsx)(n.p,{children:"arguments to be passed to the pageFunction"})})]})]})]}),"\n",(0,t.jsx)(n.p,{children:(0,t.jsx)(n.strong,{children:"Returns:"})}),"\n",(0,t.jsx)(n.p,{children:"Promise<Awaited<ReturnType<Func>>>"}),"\n",(0,t.jsxs)(n.p,{children:["the return value of ",(0,t.jsx)(n.code,{children:"pageFunction"}),"."]}),"\n",(0,t.jsx)(n.h2,{id:"example-1",children:"Example 1"}),"\n",(0,t.jsx)(n.pre,{children:(0,t.jsx)(n.code,{className:"language-ts",children:'const result = await frame.evaluate(() => {\n  return Promise.resolve(8 * 7);\n});\nconsole.log(result); // prints "56"\n'})}),"\n",(0,t.jsx)(n.p,{children:"You can pass a string instead of a function (although functions are recommended as they are easier to debug and use with TypeScript):"}),"\n",(0,t.jsx)(n.h2,{id:"example-2",children:"Example 2"}),"\n",(0,t.jsx)(n.pre,{children:(0,t.jsx)(n.code,{className:"language-ts",children:"const aHandle = await page.evaluate('1 + 2');\n"})}),"\n",(0,t.jsxs)(n.p,{children:["To get the best TypeScript experience, you should pass in as the generic the type of ",(0,t.jsx)(n.code,{children:"pageFunction"}),":"]}),"\n",(0,t.jsx)(n.pre,{children:(0,t.jsx)(n.code,{className:"language-ts",children:"con