puppeteer/new-docs/puppeteer.elementhandle._eval.md
Jack Franklin 6474edb9ba
feat(types): add types for $eval (#6135)
This pulls in the types (based on the DefinitelyTyped repo) for
`page.$eval` (and the `$eval` method on other classes). The `$eval`
method is quite hard to type due to the way we wrap and unwrap
ElementHandles that are passed to / returned from the `pageFunction`
that users provide.

Longer term we can improve the types by providing type overloads as
DefinitelyTyped does but I've deferred that for now (see the `TODO` in
the code for more details).
2020-07-02 10:09:34 +01:00

1.5 KiB

Home > puppeteer > ElementHandle > $eval

ElementHandle.$eval() method

This method runs document.querySelector within the element and passes it as the first argument to pageFunction. If there's no element matching selector, the method throws an error.

If pageFunction returns a Promise, then frame.$eval would wait for the promise to resolve and return its value.

Signature:

$eval<ReturnType>(selector: string, pageFunction: (element: Element, ...args: unknown[]) => ReturnType | Promise<ReturnType>, ...args: SerializableOrJSHandle[]): Promise<WrapElementHandle<ReturnType>>;

Parameters

Parameter Type Description
selector string
pageFunction (element: Element, ...args: unknown[]) => ReturnType | Promise<ReturnType>
args SerializableOrJSHandle[]

Returns:

Promise<WrapElementHandle<ReturnType>>

Example

const tweetHandle = await page.$('.tweet');
expect(await tweetHandle.$eval('.like', node => node.innerText)).toBe('100');
expect(await tweetHandle.$eval('.retweets', node => node.innerText)).toBe('10');