Page | /tests/deps.ts | fresh@1.5.2

method Page.prototype.evaluate

import { Page } from "https://dotland.deno.dev/x/fresh@1.5.2/tests/deps.ts";

evaluate<Params extends unknown[], Func extends EvaluateFunc<Params> = EvaluateFunc<Params>>(pageFunction: Func | string, ...args: Params): Promise<Awaited<ReturnType<Func>>>

Evaluates a function in the page's context and returns the result.

If the function passed to page.evaluteHandle returns a Promise, the function will wait for the promise to resolve and return its value.

Examples

Example 1

const result = await frame.evaluate(() => {
  return Promise.resolve(8 * 7);
});
console.log(result); // prints "56"

You can pass a string instead of a function (although functions are recommended as they are easier to debug and use with TypeScript):

Example 2

const aHandle = await page.evaluate('1 + 2');

To get the best TypeScript experience, you should pass in as the generic the type of pageFunction:

const aHandle = await page.evaluate(() => 2);

{@link ElementHandle} instances (including {@link JSHandle}s) can be passed as arguments to the pageFunction:

const bodyHandle = await page.$('body');
const html = await page.evaluate(body => body.innerHTML, bodyHandle);
await bodyHandle.dispose();

Type Parameters

Params extends unknown[]

optional

Func extends EvaluateFunc<Params> = EvaluateFunc<Params>

Parameters

pageFunction: Func | string

a function that is run within the page

...args: Params

arguments to be passed to the pageFunction

Returns

Promise<Awaited<ReturnType<Func>>>

the return value of pageFunction.