74 lines
2.3 KiB
Markdown
74 lines
2.3 KiB
Markdown
|
---
|
||
|
|
sidebar_label: Page.evaluateHandle
|
||
|
|
---
|
||
|
|
|
||
|
|
# Page.evaluateHandle() method
|
||
|
|
|
||
|
|
**Signature:**
|
||
|
|
|
||
|
|
```typescript
|
||
|
|
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](./puppeteer.handlefor.md)<Awaited<ReturnType<Func>>>>
|
||
|
|
|
||
|
|
## Remarks
|
||
|
|
|
||
|
|
The only difference between [page.evaluate](./puppeteer.page.evaluate.md) 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
|
||
|
|
|
||
|
|
```ts
|
||
|
|
const aHandle = await page.evaluateHandle('document');
|
||
|
|
```
|
||
|
|
|
||
|
|
## Example 2
|
||
|
|
|
||
|
|
[JSHandle](./puppeteer.jshandle.md) instances can be passed as arguments to the `pageFunction`:
|
||
|
|
|
||
|
|
```ts
|
||
|
|
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](./puppeteer.jshandle.md), but if `pageFunction` returns a reference to an element, you instead get an [ElementHandle](./puppeteer.elementhandle.md) back:
|
||
|
|
|
||
|
|
## Example 3
|
||
|
|
|
||
|
|
```ts
|
||
|
|
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:
|
||
|
|
|
||
|
|
```ts
|
||
|
|
const button = await page.evaluateHandle<ElementHandle>(...);
|
||
|
|
```
|