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Version: 22.12.0

Frame.waitForFunction() method

Signature:

class Frame {
waitForFunction<
Params extends unknown[],
Func extends EvaluateFunc<Params> = EvaluateFunc<Params>,
>(
pageFunction: Func | string,
options?: FrameWaitForFunctionOptions,
...args: Params
): Promise<HandleFor<Awaited<ReturnType<Func>>>>;
}

Parameters

Parameter

Type

Description

pageFunction

Func | string

the function to evaluate in the frame context.

options

FrameWaitForFunctionOptions

(Optional) options to configure the polling method and timeout.

args

Params

arguments to pass to the pageFunction.

Returns:

Promise<HandleFor<Awaited<ReturnType<Func>>>>

the promise which resolve when the pageFunction returns a truthy value.

Example

The waitForFunction can be used to observe viewport size change:

import puppeteer from 'puppeteer';

(async () => {
. const browser = await puppeteer.launch();
. const page = await browser.newPage();
. const watchDog = page.mainFrame().waitForFunction('window.innerWidth < 100');
. page.setViewport({width: 50, height: 50});
. await watchDog;
. await browser.close();
})();

To pass arguments from Node.js to the predicate of page.waitForFunction function:

const selector = '.foo';
await frame.waitForFunction(
selector => !!document.querySelector(selector),
{}, // empty options object
selector
);