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46fc6ca41a
* feat(types): improve typing of `.evaluate()` This is the start of the work to take the types from the `@types/puppeteer` repository and port them into our repo so we can ship our built-in types out the box. This change types the `evaluate` function properly. It takes a generic type which is the type of the function you're passing, and the arguments and the return that you get back from the `evaluate` call are typed correctly.
50 lines
1.4 KiB
Markdown
50 lines
1.4 KiB
Markdown
<!-- Do not edit this file. It is automatically generated by API Documenter. -->
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[Home](./index.md) > [puppeteer](./puppeteer.md) > [ElementHandle](./puppeteer.elementhandle.md) > [$$eval](./puppeteer.elementhandle.__eval.md)
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## ElementHandle.$$eval() method
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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.
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If `pageFunction` returns a Promise, then `frame.$$eval` would wait for the promise to resolve and return its value.
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<b>Signature:</b>
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```typescript
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$$eval<ReturnType extends any>(selector: string, pageFunction: EvaluateFn | string, ...args: SerializableOrJSHandle[]): Promise<ReturnType>;
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```
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## Parameters
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| Parameter | Type | Description |
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| --- | --- | --- |
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| selector | string | |
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| pageFunction | [EvaluateFn](./puppeteer.evaluatefn.md) \| string | |
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| args | [SerializableOrJSHandle](./puppeteer.serializableorjshandle.md)<!-- -->\[\] | |
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<b>Returns:</b>
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Promise<ReturnType>
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## Example 1
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```html
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<div class="feed">
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<div class="tweet">Hello!</div>
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<div class="tweet">Hi!</div>
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</div>
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```
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## Example 2
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```js
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const feedHandle = await page.$('.feed');
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expect(await feedHandle.$$eval('.tweet', nodes => nodes.map(n => n.innerText)))
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.toEqual(['Hello!', 'Hi!']);
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```
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