import { Page } from "https://deno.land/x/pptr@1.2.0/mod.ts";
This method runs document.querySelector within the page and passes the
result as the first argument to the pageFunction.
Examples
Example 1
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.$eval('.main-container', el => el.outerHTML);
If you are using TypeScript, you may have to provide an explicit type to the
first argument of the pageFunction.
By default it is typed as Element, but you may need to provide a more
specific sub-type:
Example 2
Example 2
// if you don't provide HTMLInputElement here, TS will error
// as `value` is not on `Element`
const searchValue = await page.$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 $eval:
Example 3
Example 3
// The compiler can infer the return type in this case, but if it can't
// or if you want to be more explicit, provide it as the generic type.
const searchValue = await page.$eval<string>(
'#search', (el: HTMLInputElement) => el.value
);
Parameters
- the selector to query for
pageFunction: (element: Element, ...args: unknown[]) => ReturnType | Promise<ReturnType>
- the function to be evaluated in the page context.
Will be passed the result of
document.querySelector(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.