name <string> Name of the function on the window objectpuppeteerFunction <function> Callback function which will be called in Puppeteer‘s context.The method adds a function called name on the page‘s window object. When called, the function executes puppeteerFunction in node.js and returns a Promise which resolves to the return value of puppeteerFunction.
If the puppeteerFunction returns a Promise, it will be awaited.
NOTE Functions installed via
page.exposeFunctionsurvive navigations.
An example of adding an md5 function into the page:
const puppeteer = require(‘puppeteer‘);
const crypto = require(‘crypto‘);
puppeteer.launch().then(async browser => {
const page = await browser.newPage();
page.on(‘console‘, msg => console.log(msg.text()));
await page.exposeFunction(‘md5‘, text =>
crypto.createHash(‘md5‘).update(text).digest(‘hex‘)
);
await page.evaluate(async () => {
// use window.md5 to compute hashes
const myString = ‘PUPPETEER‘;
const myHash = await window.md5(myString);
console.log(`md5 of ${myString} is ${myHash}`);
});
await browser.close();
});
An example of adding a window.readfile function into the page:
const puppeteer = require(‘puppeteer‘);
const fs = require(‘fs‘);
puppeteer.launch().then(async browser => {
const page = await browser.newPage();
page.on(‘console‘, msg => console.log(msg.text()));
await page.exposeFunction(‘readfile‘, async filePath => {
return new Promise((resolve, reject) => {
fs.readFile(filePath, ‘utf8‘, (err, text) => {
if (err)
reject(err);
else
resolve(text);
});
});
});
await page.evaluate(async () => {
// use window.readfile to read contents of a file
const content = await window.readfile(‘/etc/hosts‘);
console.log(content);
});
await browser.close();
});
原文：https://www.cnblogs.com/justart/p/9747724.html