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.
39 lines
1.3 KiB
Markdown
39 lines
1.3 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.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.
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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
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```js
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const tweetHandle = await page.$('.tweet');
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expect(await tweetHandle.$eval('.like', node => node.innerText)).toBe('100');
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expect(await tweetHandle.$eval('.retweets', node => node.innerText)).toBe('10');
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```
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