2.2 KiB
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| Page.evaluateHandle |
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.evaluteHandle 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>(...);