puppeteer/docs/api/puppeteer.page._eval.md

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Page.$eval

Page.$eval() method

This method finds the first element within the page that matches the selector and passes the result as the first argument to the pageFunction.

Signature:

class Page {
  $eval<
    Selector extends string,
    Params extends unknown[],
    Func extends EvaluateFuncWith<NodeFor<Selector>, Params> = EvaluateFuncWith<
      NodeFor<Selector>,
      Params
    >,
  >(
    selector: Selector,
    pageFunction: Func | string,
    ...args: Params
  ): Promise<Awaited<ReturnType<Func>>>;
}

Parameters

Parameter	Type	Description
selector	Selector	selector to query page for. CSS selectors can be passed as-is and a Puppeteer-specific seletor syntax allows quering by text, a11y role and name, and xpath and combining these queries across shadow roots. Alternatively, you can specify a selector type using a prefix prefix.
pageFunction	Func | string	the function to be evaluated in the page context. Will be passed the result of the element matching the selector as its first argument.
args	Params	any additional arguments to pass through to pageFunction.

**Returns:**

Promise<Awaited<ReturnType<Func>>>

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 no element is found matching selector, the method will throw an error.

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

Example 1

const searchValue = await page.$eval('#search', el => el.value);
const preloadHref = await page.$eval('link[rel=preload]', el => el.href);
const html = await page.$eval('.main-container', el => el.outerHTML);

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`
const searchValue = await page.$eval(
  '#search',
  (el: HTMLInputElement) => el.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 searchValue = await page.$eval<string>(
  '#search',
  (el: HTMLInputElement) => el.value
);