puppeteer/website/versioned_docs/version-21.3.8/api/puppeteer.webworker.evaluate.md

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WebWorker.evaluate

WebWorker.evaluate() method

If the function passed to the worker.evaluate returns a Promise, then worker.evaluate would wait for the promise to resolve and return its value. If the function passed to the worker.evaluate returns a non-serializable value, then worker.evaluate resolves to undefined. DevTools Protocol also supports transferring some additional values that are not serializable by JSON: -0, NaN, Infinity, -Infinity, and bigint literals. Shortcut for await worker.executionContext()).evaluate(pageFunction, ...args).

Signature:

class WebWorker {
  evaluate<
    Params extends unknown[],
    Func extends EvaluateFunc<Params> = EvaluateFunc<Params>,
  >(
    pageFunction: Func | string,
    ...args: Params
  ): Promise<Awaited<ReturnType<Func>>>;
}

Parameters

Parameter	Type	Description
pageFunction	Func | string	Function to be evaluated in the worker context.
args	Params	Arguments to pass to pageFunction.

Returns:

Promise<Awaited<ReturnType<Func>>>

Promise which resolves to the return value of pageFunction.