puppeteer/docs/api/puppeteer.executioncontext.evaluatehandle.md
2022-07-05 15:41:43 +02:00

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ExecutionContext.evaluateHandle

ExecutionContext.evaluateHandle() method

Signature:

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

Parameters

Parameter Type Description
pageFunction Func | string a function to be evaluated in the executionContext
args Params argument to pass to the page function

Returns:

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

A promise that resolves to the return value of the given function as an in-page object (a JSHandle).

Remarks

The only difference between executionContext.evaluate and executionContext.evaluateHandle is that executionContext.evaluateHandle returns an in-page object (a JSHandle). If the function passed to the executionContext.evaluateHandle returns a Promise, then executionContext.evaluateHandle would wait for the promise to resolve and return its value.

Example 1

const context = await page.mainFrame().executionContext();
const aHandle = await context.evaluateHandle(() => Promise.resolve(self));
aHandle; // Handle for the global object.

Example 2

A string can also be passed in instead of a function.

// Handle for the '3' * object.
const aHandle = await context.evaluateHandle('1 + 2');

Example 3

JSHandle instances can be passed as arguments to the executionContext.* evaluateHandle:

const aHandle = await context.evaluateHandle(() => document.body);
const resultHandle = await context.evaluateHandle(body => body.innerHTML, * aHandle);
console.log(await resultHandle.jsonValue()); // prints body's innerHTML
await aHandle.dispose();
await resultHandle.dispose();