puppeteer/docs/api/puppeteer.realm.waitforfunction.md

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Realm.waitForFunction

Realm.waitForFunction() method

Waits for a function to return a truthy value when evaluated in the realm's context.

Arguments can be passed from Node.js to pageFunction.

Signature

class Realm {
  waitForFunction<
    Params extends unknown[],
    Func extends EvaluateFunc<Params> = EvaluateFunc<Params>,
  >(
    pageFunction: Func | string,
    options?: {
      polling?: 'raf' | 'mutation' | number;
      timeout?: number;
      root?: ElementHandle<Node>;
      signal?: AbortSignal;
    },
    ...args: Params
  ): Promise<HandleFor<Awaited<ReturnType<Func>>>>;
}

Parameters

Parameter	Type	Description
pageFunction	Func | string	A function to evaluate in the realm.
options	{ polling?: 'raf' | 'mutation' | number; timeout?: number; root?: ElementHandle<Node>; signal?: AbortSignal; }	(Optional) Options for polling and timeouts.
args	Params	Arguments to pass to the function.

Returns:

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

A promise that resolves when the function returns a truthy value.

Example

const selector = '.foo';
await realm.waitForFunction(
  selector => !!document.querySelector(selector),
  {},
  selector,
);