为什么我不能使用Puppeteer在暴露函数()中访问“窗口"?

我有一个非常简单的木偶脚本，该脚本使用

I have a very simple Puppeteer script that uses exposeFunction() to run something inside headless Chrome.

(async function(){

    var log = console.log.bind(console),
        puppeteer = require('puppeteer');


    const browser = await puppeteer.launch();
    const page = await browser.newPage();

    var functionToInject = function(){
        return window.navigator.appName;
    }

    await page.exposeFunction('functionToInject', functionToInject);

    var data = await page.evaluate(async function(){
        console.log('woo I run inside a browser')
        return await functionToInject();
    });

    console.log(data);

    await browser.close();

})()

此操作失败，并显示以下信息:

This fails with:

ReferenceError: window is not defined

指的是注入函数.如何在无头Chrome中访问window?

Which refers to the injected function. How can I access window inside the headless Chrome?

我知道我可以代替evaluate()，但这不适用于我动态传递的函数:

I know I can do evaluate() instead, but this doesn't work with a function I pass dynamically:

(async function(){

    var log = console.log.bind(console),
        puppeteer = require('puppeteer');

    const browser = await puppeteer.launch();
    const page = await browser.newPage();

    var data = await page.evaluate(async function(){
        console.log('woo I run inside a browser')
        return window.navigator.appName;
    });

    console.log(data);

    await browser.close();

})()