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This change started as a small change to pull types from DefinitelyTyped over to
Puppeteer for the `evaluateHandle` function but instead ended up also fixing
what looks to be a long standing issue with our existing documentation.
`evaluateHandle` can in fact return an `ElementHandle` rather than a `JSHandle`.
Note that `ElementHandle` extends `JSHandle` so whilst the docs are technically
correct (all ElementHandles are JSHandles) it's confusing because JSHandles
don't have methods like `click` on them, but ElementHandles do.
if you return something that is an HTML element:
```
const button = page.evaluateHandle(() => document.querySelector('button'));
// this is an ElementHandle, not a JSHandle
```
Therefore I've updated the original docs and added a large explanation to the
TSDoc for `page.evaluateHandle`.
In TypeScript land we'll assume the function will return a `JSHandle` but you
can tell TS otherwise via the generic argument, which can only be `JSHandle`
(the default) or `ElementHandle`:
```
const button = page.evaluateHandle<ElementHandle>(() => document.querySelector('button'));
```
866 B
866 B
Home > puppeteer > Frame > waitForFunction
Frame.waitForFunction() method
Signature:
waitForFunction(pageFunction: Function | string, options?: {
polling?: string | number;
timeout?: number;
}, ...args: SerializableOrJSHandle[]): Promise<JSHandle>;
Parameters
| Parameter | Type | Description |
|---|---|---|
| pageFunction | Function | string | |
| options | { polling?: string | number; timeout?: number; } | |
| args | SerializableOrJSHandle[] |
Returns:
Promise<JSHandle>