Puppeteer detect when the new tab is opened

问题

A very simple question.

My web app opens a new tab under some conditions. But when I try to get all tabs (await browser.pages()) I get only one, initial page back.

How can I get the new page's object in my code?

This happens when you don't create new tab with puppeteer with await browser.newPage(), but when you do something like this:

await (await browser.pages())[0].evaluate(() => {
    window.open('http://www.example.com', '_blank');
});

The page won't be available in the browser.pages() response.

Thanks!

回答1:

It's hard without knowing your conditions when the app opens a new tab. It works perfectly fine for me. Here is a code demonstrating how I can use it. Read the comments to understand the steps.

UPDATED:

window.open() doesn't return a promise, thus browser.pages() is executed faster than the browser can create and report the event. We can use the targetcreated event to know if any new tab is created.

browser.on('targetcreated', function(){
    console.log('New Tab Created');
})

If you wait for a while or return a promise, you will see it reports it within browser.pages() count.

await tabOne.evaluate(() => {
    window.open('http://www.example.com', '_blank');
  });
await tabOne.waitFor(2000); // await for a while
console.log("current page count ", (await browser.pages()).length); // 3

Here is the final code.

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();

  browser.on('targetcreated', function(){
    console.log('New Tab Created');
  })

  // get current tab count
  console.log("current page count ", (await browser.pages()).length); // 3

  // create a new tab
  await browser.newPage();
  // lets see if tab increased
  console.log("current page count ", (await browser.pages()).length); // 3

  // use destructuring for easier usage
  const [tabOne, tabTwo] = (await browser.pages());

  // use the tabs aka Page objects properly
  await tabOne.goto('https://example.com');
  console.log("Tab One Title ",await tabOne.title()); // Example Domain

  // use the tabs aka Page objects properly
  await tabTwo.goto('https://example.com');
  console.log("Tab Two Title ",await tabTwo.title()); // Example Domain

  await tabOne.evaluate(() => {
    window.open('http://www.example.com', '_blank');
  });
  await tabOne.waitFor(2000); // wait for a while
  console.log("current page count ", (await browser.pages()).length); // 3

  // close the browser
  await browser.close();
})();

If you run it, you'll get the result in following sequence.

/*
current page count  1
New Tab Created
current page count  2
Tab One Title  Example Domain
Tab Two Title  Example Domain
New Tab Created
current page count  3
*/

回答2:

This code will catch the new page in a new tab if it was opened by clicking a link in the original page.

//save target of original page to know that this was the opener:     
const pageTarget = page.target();
//execute click on first tab that triggers opening of new tab:
await page.click('#selector');
//check that the first page opened this new page:
const newTarget = await browser.waitForTarget(target => target.opener() === pageTarget);
//get the new page object:
const newPage = await newTarget.page();

来源：https://stackoverflow.com/questions/49050003/puppeteer-detect-when-the-new-tab-is-opened

标签

javascript

google-chrome

Puppeteer