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polling?: string ","|"," number; }"),(0,r.kt)("td",{parentName:"tr",align:null},(0,r.kt)("i",null,"(Optional)")," Optional waiting parameters - ",(0,r.kt)("code",null,"polling")," - An interval at which the ",(0,r.kt)("code",null,"pageFunction")," is executed, defaults to ",(0,r.kt)("code",null,"raf"),". If ",(0,r.kt)("code",null,"polling")," is a number, then it is treated as an interval in milliseconds at which the function would be executed. If polling is a string, then it can be one of the following values: - ",(0,r.kt)("code",null,"raf")," - to constantly execute ",(0,r.kt)("code",null,"pageFunction")," in ",(0,r.kt)("code",null,"requestAnimationFrame")," callback. This is the tightest polling mode which is suitable to observe styling changes. - ",(0,r.kt)("code",null,"mutation"),"- to execute pageFunction on every DOM mutation. - ",(0,r.kt)("code",null,"timeout")," - maximum time to wait for in milliseconds. Defaults to ",(0,r.kt)("code",null,"30000")," (30 seconds). Pass ",(0,r.kt)("code",null,"0")," to disable timeout. The default value can be changed by using the ",(0,r.kt)("a",{parentName:"td",href:"/next/api/puppeteer.page.setdefaulttimeout"},"Page.setDefaultTimeout()")," method.")),(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 pass to ",(0,r.kt)("code",null,"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:"/next/api/puppeteer.handlefor"},"HandleFor"),"<","Awaited","<","ReturnType","<","Func",">",">",">",">"),(0,r.kt)("p",null,"A ",(0,r.kt)("inlineCode",{parentName:"p"},"Promise")," which resolves to a JSHandle/ElementHandle of the the ",(0,r.kt)("inlineCode",{parentName:"p"},"pageFunction"),"'s return value."),(0,r.kt)("h2",{id:"example-1"},"Example 1"),(0,r.kt)("p",null,"The ",(0,r.kt)("a",{parentName:"p",href:"/next/api/puppeteer.page.waitforfunction"},"Page.waitForFunction()")," can be used to observe viewport size change:"),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-ts"},"const puppeteer = require('puppeteer');\n(async () => {\nconst browser = await puppeteer.launch();\nconst page = await browser.newPage();\nconst watchDog = page.waitForFunction('window.innerWidth < 100');\nawait page.setViewport({ width: 50, height: 50 });\nawait watchDog;\nawait browser.close();\n})();\n")),(0,r.kt)("h2",{id:"example-2"},"Example 2"),(0,r.kt)("p",null,"To pass arguments from node.js to the predicate of ",(0,r.kt)("a",{parentName:"p",href:"/next/api/puppeteer.page.waitforfunction"},"Page.waitForFunction()")," function:"),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-ts"},"const selector = '.foo';\nawait page.waitForFunction(\n(selector) => !!document.querySelector(selector),\n{},\nselector\n);\n")),(0,r.kt)("h2",{id:"example-3"},"Example 3"),(0,r.kt)("p",null,"The predicate of ",(0,r.kt)("a",{parentName:"p",href:"/next/api/puppeteer.page.waitforfunction"},"Page.waitForFunction()")," can be asynchronous too:"),(0,r.kt)("pre",null,(0,r.kt)("code",{parentName:"pre",className:"language-ts"},"const username = 'github-username';\nawait page.waitForFunction(\nasync (username) => {\nconst githubResponse = await fetch(\n `https://api.github.com/users/${username}`\n);\nconst githubUser = await githubResponse.json();\n// show the avatar\nconst img = document.createElement('img');\nimg.src = githubUser.avatar_url;\n// wait 3 seconds\nawait new Promise((resolve, reject) => setTimeout(resolve, 3000));\nimg.remove();\n},\n{},\nusername\n);\n")))}s.isMDXComponent=!0}}]);