puppeteer/assets/js/f609e1b8.10e5eff1.js

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puppeteer &gt; Page &gt; $$eval",source:"@site/docs/puppeteer.page.__eval.md",sourceDirName:".",slug:"/puppeteer.page.__eval",permalink:"/puppeteer/docs/next/puppeteer.page.__eval",editUrl:"https://github.com/facebook/puppeteer/edit/main/website/docs/puppeteer.page.__eval.md",version:"current",frontMatter:{},sidebar:"docs",previous:{title:"puppeteer.page.__",permalink:"/puppeteer/docs/next/puppeteer.page.__"},next:{title:"puppeteer.page._eval",permalink:"/puppeteer/docs/next/puppeteer.page._eval"}},m=[{value:"Page.$$eval() method",id:"pageeval-method",children:[]},{value:"Parameters",id:"parameters",children:[]},{value:"Remarks",id:"remarks",children:[]},{value:"Example 1",id:"example-1",children:[]},{value:"Example 2",id:"example-2",children:[]},{value:"Example 3",id:"example-3",children:[]}],s={toc:m};function c(e){var t=e.components,n=(0,a.Z)(e,l);return(0,p.kt)("wrapper",(0,r.Z)({},s,n,{components:t,mdxType:"MDXLayout"}),(0,p.kt)("p",null,(0,p.kt)("a",{parentName:"p",href:"/puppeteer/docs/next/index"},"Home")," ",">"," ",(0,p.kt)("a",{parentName:"p",href:"/puppeteer/docs/next/puppeteer"},"puppeteer")," ",">"," ",(0,p.kt)("a",{parentName:"p",href:"/puppeteer/docs/next/puppeteer.page"},"Page")," ",">"," ",(0,p.kt)("a",{parentName:"p",href:"/puppeteer/docs/next/puppeteer.page.__eval"},"$$eval")),(0,p.kt)("h2",{id:"pageeval-method"},"Page.$$eval() method"),(0,p.kt)("p",null,"This method runs ",(0,p.kt)("inlineCode",{parentName:"p"},"Array.from(document.querySelectorAll(selector))")," within the page and passes the result as the first argument to the ",(0,p.kt)("inlineCode",{parentName:"p"},"pageFunction"),"."),(0,p.kt)("b",null,"Signature:"),(0,p.kt)("pre",null,(0,p.kt)("code",{parentName:"pre",className:"language-typescript"},"$$eval<ReturnType>(selector: string, pageFunction: (elements: Element[], ...args: unknown[]) => ReturnType | Promise<ReturnType>, ...args: SerializableOrJSHandle[]): Promise<WrapElementHandle<ReturnType>>;\n")),(0,p.kt)("h2",{id:"parameters"},"Parameters"),(0,p.kt)("table",null,(0,p.kt)("thead",{parentName:"table"},(0,p.kt)("tr",{parentName:"thead"},(0,p.kt)("th",{parentName:"tr",align:null},"Parameter"),(0,p.kt)("th",{parentName:"tr",align:null},"Type"),(0,p.kt)("th",{parentName:"tr",align:null},"Description"))),(0,p.kt)("tbody",{parentName:"table"},(0,p.kt)("tr",{parentName:"tbody"},(0,p.kt)("td",{parentName:"tr",align:null},"selector"),(0,p.kt)("td",{parentName:"tr",align:null},"string"),(0,p.kt)("td",{parentName:"tr",align:null},"the ",(0,p.kt)("a",{parentName:"td",href:"https://developer.mozilla.org/en-US/docs/Web/CSS/CSS_Selectors"},"selector")," to query for")),(0,p.kt)("tr",{parentName:"tbody"},(0,p.kt)("td",{parentName:"tr",align:null},"pageFunction"),(0,p.kt)("td",{parentName:"tr",align:null},"(elements: Element","[","]",", ...args: unknown","[","]",") =",">"," ReturnType ","|"," Promise","<","ReturnType",">"),(0,p.kt)("td",{parentName:"tr",align:null},"the function to be evaluated in the page context. Will be passed the result of ",(0,p.kt)("code",null,"Array.from(document.querySelectorAll(selector))")," as its first argument.")),(0,p.kt)("tr",{parentName:"tbody"},(0,p.kt)("td",{parentName:"tr",align:null},"args"),(0,p.kt)("td",{parentName:"tr",align:null},(0,p.kt)("a",{parentName:"td",href:"/puppeteer/docs/next/puppeteer.serializableorjshandle"},"SerializableOrJSHandle"),"[","]"),(0,p.kt)("td",{parentName:"tr",align:null},"any additional arguments to pass through to ",(0,p.kt)("code",null,"pageFunction"),".")))),(0,p.kt)("b",null,"Returns:"),(0,p.kt)("p",null,"Promise","<",(0,p.kt)("a",{parentName:"p",href:"/puppeteer/docs/next/puppeteer.wrapelementhandle"},"WrapElementHandle"),"<","ReturnType",">",">"),(0,p.kt)("p",null,"The result of calling ",(0,p.kt)("inlineCode",{parentName:"p"},"pageFunction"),". If it returns an element it is wrapped in an ",(0,p.kt)("a",{parentName:"p",href:"/puppeteer/docs/next/puppeteer.elementhandle"},"ElementHandle"),", else the raw value itself is returned."),(0,p.kt)("h2",{id:"remarks"},"Remarks"),(0,p.kt)("p",null,"If ",(0,p.kt)("inlineCode",{parentName:"p"},"pageFunction")," returns a promise ",(0,p.kt)("inlineCode",{parentName:"p"},"$$eval")," will wait for the promise to resolve and then return its value."),(0,p.kt)("h2",{id:"example-1"},"Example 1"),(0,p.kt)("pre",null,(0,p.kt)("code",{parentName:"pre"},"// get the amount of divs on the page\nconst divCount = await page.$$eval('div', divs => divs.length);\n\n// get the text content of all the `.options` elements:\nconst options = await page.$$eval('div > span.options', options => {\n  return options.map(option => option.textContent)\n});\n")),(0,p.kt)("p",null,"If you are using TypeScript, you may have to provide an explicit type to the first argument of the ",(0,p.kt)("inlineCode",{parentName:"p"},"pageFunction"),". By default it is typed as ",(0,p.kt)("inlineCode",{parentName:"p"},"Element[]"),", but you may need to provide a more specific sub-type:"),(0,p.kt)("h2",{id:"example-2"},"Example 2"),(0,p.kt)("pre",null,(0,p.kt)("code",{parentName:"pre"},"// if you don't provide HTMLInputElement here, TS will error\n// as `value` is not on `Element`\nawait page.$$eval('input', (elements: HTMLInputElement[]) => {\n  return elements.map(e => e.value);\n});\n")),(0,p.kt)("p",null,"The compiler should be able to infer the return type from the ",(0,p.kt)("inlineCode",{parentName:"p"},"pageFunction")," you provide. 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