Page.evaluateHandle() method
Signature
class Page {
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 that is run within the page |
args | Params | arguments to be passed to the pageFunction |
Returns:
Promise<HandleFor<Awaited<ReturnType<Func>>>>
Remarks
The only difference between page.evaluate and page.evaluateHandle
is that evaluateHandle
will return the value wrapped in an in-page object.
If the function passed to page.evaluateHandle
returns a Promise, the function will wait for the promise to resolve and return its value.
You can pass a string instead of a function (although functions are recommended as they are easier to debug and use with TypeScript):
Example 1
const aHandle = await page.evaluateHandle('document');
Example 2
JSHandle instances can be passed as arguments to the pageFunction
:
const aHandle = await page.evaluateHandle(() => document.body);
const resultHandle = await page.evaluateHandle(body => body.innerHTML, aHandle);
console.log(await resultHandle.jsonValue());
await resultHandle.dispose();
Most of the time this function returns a JSHandle, but if pageFunction
returns a reference to an element, you instead get an ElementHandle back:
Example 3
const button = await page.evaluateHandle(() =>
document.querySelector('button')
);
// can call `click` because `button` is an `ElementHandle`
await button.click();
The TypeScript definitions assume that evaluateHandle
returns a JSHandle
, but if you know it's going to return an ElementHandle
, pass it as the generic argument:
const button = await page.evaluateHandle<ElementHandle>(...);