puppeteer.page.__eval.md

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Page.$$eval() method

This method runs Array.from(document.querySelectorAll(selector)) within the page and passes the result as the first argument to the pageFunction.

Signature:

$$eval<ReturnType>(selector: string, pageFunction: (elements: Element[], ...args: unknown[]) => ReturnType | Promise<ReturnType>, ...args: SerializableOrJSHandle[]): Promise<WrapElementHandle<ReturnType>>;

Parameters

Parameter	Type	Description
selector	string	the selector to query for
pageFunction	(elements: Element[], ...args: unknown[]) => ReturnType | Promise<ReturnType>	the function to be evaluated in the page context. Will be passed the result of Array.from(document.querySelectorAll(selector)) as its first argument.
args	SerializableOrJSHandle[]	any additional arguments to pass through to pageFunction.

Returns:

Promise<WrapElementHandle<ReturnType>>

The result of calling pageFunction. If it returns an element it is wrapped in an ElementHandle, else the raw value itself is returned.

Remarks

If pageFunction returns a promise $$eval will wait for the promise to resolve and then return its value.

Example 1

// get the amount of divs on the page
const divCount = await page.$$eval('div', divs => divs.length);

// get the text content of all the `.options` elements:
const options = await page.$$eval('div > span.options', options => {
  return options.map(option => option.textContent)
});

If you are using TypeScript, you may have to provide an explicit type to the first argument of the pageFunction. By default it is typed as Element[], but you may need to provide a more specific sub-type:

Example 2

// if you don't provide HTMLInputElement here, TS will error
// as `value` is not on `Element`
await page.$$eval('input', (elements: HTMLInputElement[]) => {
  return elements.map(e => e.value);
});

The compiler should be able to infer the return type from the pageFunction you provide. If it is unable to, you can use the generic type to tell the compiler what return type you expect from $$eval:

Example 3

// The compiler can infer the return type in this case, but if it can't
// or if you want to be more explicit, provide it as the generic type.
const allInputValues = await page.$$eval<string[]>(
 'input', (elements: HTMLInputElement[]) => elements.map(e => e.textContent)
);