puppeteer/new-docs/puppeteer.elementhandle.__eval.md
Jack Franklin 5049b83186
feat(types): add types for page.$$eval (#6139)
* feat(types): add types for `page.$$eval`

* Add new-docs for $$eval

* fix example

* linting
2020-07-03 15:23:51 +01:00

50 lines
1.6 KiB
Markdown

<!-- Do not edit this file. It is automatically generated by API Documenter. -->
[Home](./index.md) &gt; [puppeteer](./puppeteer.md) &gt; [ElementHandle](./puppeteer.elementhandle.md) &gt; [$$eval](./puppeteer.elementhandle.__eval.md)
## ElementHandle.$$eval() method
This method runs `document.querySelectorAll` 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.$$eval` would wait for the promise to resolve and return its value.
<b>Signature:</b>
```typescript
$$eval<ReturnType>(selector: string, pageFunction: (elements: Element[], ...args: unknown[]) => ReturnType | Promise<ReturnType>, ...args: SerializableOrJSHandle[]): Promise<WrapElementHandle<ReturnType>>;
```
## Parameters
| Parameter | Type | Description |
| --- | --- | --- |
| selector | string | |
| pageFunction | (elements: Element\[\], ...args: unknown\[\]) =&gt; ReturnType \| Promise&lt;ReturnType&gt; | |
| args | [SerializableOrJSHandle](./puppeteer.serializableorjshandle.md)<!-- -->\[\] | |
<b>Returns:</b>
Promise&lt;[WrapElementHandle](./puppeteer.wrapelementhandle.md)<!-- -->&lt;ReturnType&gt;&gt;
## Example 1
```html
<div class="feed">
<div class="tweet">Hello!</div>
<div class="tweet">Hi!</div>
</div>
```
## Example 2
```js
const feedHandle = await page.$('.feed');
expect(await feedHandle.$$eval('.tweet', nodes => nodes.map(n => n.innerText)))
.toEqual(['Hello!', 'Hi!']);
```