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context."),(0,a.kt)("h4",r({},{id:"signature"}),"Signature:"),(0,a.kt)("pre",null,(0,a.kt)("code",r({parentName:"pre"},{className:"language-typescript"}),"class Page {\n  waitForFunction<\n    Params extends unknown[],\n    Func extends EvaluateFunc<Params> = EvaluateFunc<Params>\n  >(\n    pageFunction: Func | string,\n    options?: FrameWaitForFunctionOptions,\n    ...args: Params\n  ): Promise<HandleFor<Awaited<ReturnType<Func>>>>;\n}\n")),(0,a.kt)("h2",r({},{id:"parameters"}),"Parameters"),(0,a.kt)("table",null,(0,a.kt)("thead",{parentName:"table"},(0,a.kt)("tr",{parentName:"thead"},(0,a.kt)("th",r({parentName:"tr"},{align:null}),"Parameter"),(0,a.kt)("th",r({parentName:"tr"},{align:null}),"Type"),(0,a.kt)("th",r({parentName:"tr"},{align:null}),"Description"))),(0,a.kt)("tbody",{parentName:"table"},(0,a.kt)("tr",{parentName:"tbody"},(0,a.kt)("td",r({parentName:"tr"},{align:null}),"pageFunction"),(0,a.kt)("td",r({parentName:"tr"},{align:null}),"Func ","|"," 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1"),(0,a.kt)("p",null,"The ",(0,a.kt)("a",r({parentName:"p"},{href:"/api/puppeteer.page.waitforfunction"}),"Page.waitForFunction()")," can be used to observe viewport size change:"),(0,a.kt)("pre",null,(0,a.kt)("code",r({parentName:"pre"},{className:"language-ts"}),"import puppeteer from 'puppeteer';\n(async () => {\n  const browser = await puppeteer.launch();\n  const page = await browser.newPage();\n  const watchDog = page.waitForFunction('window.innerWidth < 100');\n  await page.setViewport({width: 50, height: 50});\n  await watchDog;\n  await browser.close();\n})();\n")),(0,a.kt)("h2",r({},{id:"example-2"}),"Example 2"),(0,a.kt)("p",null,"To pass arguments from node.js to the predicate of ",(0,a.kt)("a",r({parentName:"p"},{href:"/api/puppeteer.page.waitforfunction"}),"Page.waitForFunction()")," function:"),(0,a.kt)("pre",null,(0,a.kt)("code",r({parentName:"pre"},{className:"language-ts"}),"const selector = '.foo';\nawait page.waitForFunction(\n  selector => 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