puppeteer/assets/js/71d5c8d7.34940300.js

/*! For license information please see 71d5c8d7.34940300.js.LICENSE.txt */
"use strict";(self.webpackChunkwebsite=self.webpackChunkwebsite||[]).push([[79204],{93900:(e,n,t)=>{t.r(n),t.d(n,{assets:()=>c,contentTitle:()=>l,default:()=>p,frontMatter:()=>s,metadata:()=>i,toc:()=>d});var a=t(85893),r=t(11151);const s={sidebar_label:"Page.evaluate"},l="Page.evaluate() method",i={id:"api/puppeteer.page.evaluate",title:"Page.evaluate() method",description:"Evaluates a function in the page's context and returns the result.",source:"@site/../docs/api/puppeteer.page.evaluate.md",sourceDirName:"api",slug:"/api/puppeteer.page.evaluate",permalink:"/next/api/puppeteer.page.evaluate",draft:!1,unlisted:!1,tags:[],version:"current",frontMatter:{sidebar_label:"Page.evaluate"},sidebar:"api",previous:{title:"Page.emulateVisionDeficiency",permalink:"/next/api/puppeteer.page.emulatevisiondeficiency"},next:{title:"Page.evaluateHandle",permalink:"/next/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 o(e){const n={a:"a",code:"code",h1:"h1",h2:"h2",h4:"h4",p:"p",pre:"pre",strong:"strong",table:"table",tbody:"tbody",td:"td",th:"th",thead:"thead",tr:"tr",...(0,r.a)(),...e.components};return(0,a.jsxs)(a.Fragment,{children:[(0,a.jsx)(n.h1,{id:"pageevaluate-method",children:"Page.evaluate() method"}),"\n",(0,a.jsx)(n.p,{children:"Evaluates a function in the page's context and returns the result."}),"\n",(0,a.jsxs)(n.p,{children:["If the function passed to ",(0,a.jsx)(n.code,{children:"page.evaluate"})," returns a Promise, the function will wait for the promise to resolve and return its value."]}),"\n",(0,a.jsx)(n.h4,{id:"signature",children:"Signature:"}),"\n",(0,a.jsx)(n.pre,{children:(0,a.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,a.jsx)(n.h2,{id:"parameters",children:"Parameters"}),"\n",(0,a.jsxs)(n.table,{children:[(0,a.jsx)(n.thead,{children:(0,a.jsxs)(n.tr,{children:[(0,a.jsx)(n.th,{children:"Parameter"}),(0,a.jsx)(n.th,{children:"Type"}),(0,a.jsx)(n.th,{children:"Description"})]})}),(0,a.jsxs)(n.tbody,{children:[(0,a.jsxs)(n.tr,{children:[(0,a.jsx)(n.td,{children:"pageFunction"}),(0,a.jsx)(n.td,{children:"Func | string"}),(0,a.jsx)(n.td,{children:"a function that is run within the page"})]}),(0,a.jsxs)(n.tr,{children:[(0,a.jsx)(n.td,{children:"args"}),(0,a.jsx)(n.td,{children:"Params"}),(0,a.jsx)(n.td,{children:"arguments to be passed to the pageFunction"})]})]})]}),"\n",(0,a.jsx)(n.p,{children:(0,a.jsx)(n.strong,{children:"Returns:"})}),"\n",(0,a.jsx)(n.p,{children:"Promise<Awaited<ReturnType<Func>>>"}),"\n",(0,a.jsxs)(n.p,{children:["the return value of ",(0,a.jsx)(n.code,{children:"pageFunction"}),"."]}),"\n",(0,a.jsx)(n.h2,{id:"example-1",children:"Example 1"}),"\n",(0,a.jsx)(n.pre,{children:(0,a.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,a.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,a.jsx)(n.h2,{id:"example-2",children:"Example 2"}),"\n",(0,a.jsx)(n.pre,{children:(0,a.jsx)(n.code,{className:"language-ts",children:"const aHandle = await page.evaluate('1 + 2');\n"})}),"\n",(0,a.jsxs)(n.p,{children:["To get the best TypeScript experience, you should pass in as the generic the type of ",(0,a.jsx)(n.code,{children:"pageFunction"}),":"]}),"\n",(0,a.jsx)(n.pre,{children:(0,a.jsx)(n.code,{className:"language-ts",children:"const aHandle = await page.evaluate(() => 2);\n"})}),"\n",(0,a.jsx)(n.h2,{id:"example-3",children:"Example 3"}),"\n",(0,a.jsxs)(n.p,{children:[(0,a.jsx)(n.a,{href:"/next/api/pupp