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Browser automation with Puppeteer

August 26, 2023

Puppeteer is a headless browser for automating browser tasks. Here's the list of some of the features:

  • Turn off headless mode

    const browser = await puppeteer.launch({
      headless: false
      // ...
    });

  • Resize the viewport to the window size

    const browser = await puppeteer.launch({
      // ...
      defaultViewport: null
    });

  • Emulate screen how it's shown to the user via the emulateMediaType method

    await page.emulateMediaType('screen');

  • Save the page as a PDF file with a specified path, format, scale factor, and page range

    await page.pdf({
      path: 'path.pdf',
      format: 'A3',
      scale: 1,
      pageRanges: '1-2',
      printBackground: true
    });

  • Use preexisting user's credentials to skip logging in to some websites. The user data directory is a parent of the Profile Path value from the chrome://version page.

    const browser = await puppeteer.launch({
      userDataDir: 'C:\\Users\\<USERNAME>\\AppData\\Local\\Google\\Chrome\\User Data',
      args: [],
    });

  • Use Chrome instance instead of Chromium by utilizing the Executable Path from the chrome://version URL. Close Chrome browser before running the script

    const browser = await puppeteer.launch({
      executablePath: puppeteer.executablePath('chrome'),
      // ...
    });

  • Get value based on evaluation in the browser page

    const shouldPaginate = await page.evaluate((param1, param2) => {
      // ...
    }, param1, param2);

  • Get HTML content from the specific element

    const html = await page.evaluate(
      () => document.querySelector('.field--text').outerHTML,
    );

  • Wait for a specific selector to be loaded. You can also provide a timeout in milliseconds

    await page.waitForSelector('.success', { timeout: 5000 });

  • Manipulate with a specific element and click on some of the elements

    await page.$eval('#header', async (headerElement) => {
      // ...
      headerElement
        .querySelectorAll('svg')
        .item(13)
        .parentNode.click();
    });

  • Extend execution of the $eval method

    const browser = await puppeteer.launch({
      // ...
      protocolTimeout: 0,
    });

  • Manipulate with multiple elements

    await page.$$eval('.some-class', async (elements) => {
      // ...
    });

  • Wait for navigation (e.g., form submitting) to be done

    await page.waitForNavigation({ waitUntil: 'networkidle0', timeout: 0 });

  • Trigger hover event on some of the elements

    await page.$eval('#header', async (headerElement) => {
      const hoverEvent = new MouseEvent('mouseover', {
        view: window,
        bubbles: true,
        cancelable: true
      });
      headerElement.dispatchEvent(hoverEvent);
    });

  • Expose a function in the browser and use it in $eval and $$eval callbacks (e.g., simulate typing using the window.type function)

    await page.exposeFunction('type', async (selector, text, options) => {
      await page.type(selector, text, options);
    });
    await page.$$eval('.some-class', async (elements) => {
      // ...
      window.type(selector, text, { delay: 0 });
    });

  • Press the Enter button after typing the input field value

    await page.type(selector, `${text}${String.fromCharCode(13)}`, options);

  • Remove the value from the input field before typing the new one

    await page.click(selector, { clickCount: 3 });
    await page.type(selector, text, options);

  • Expose a variable in the browser by passing it as the third argument for $eval and $$eval methods and use it in $eval and $$eval callbacks

    await page.$eval(
      '#element',
      async (element, customVariable) => {
        // ...
      },
      customVariable
    );

  • Mock response for the specific request

    await page.setRequestInterception(true);
    page.on('request', async function (request) {
      const url = request.url();
      if (url !== REDIRECTION_URL) {
        return request.continue();
      }
      await request.respond({
        contentType: 'text/html',
        status: 304,
        body: '<body></body>',
      });
    });

  • Intercept page redirections (via interceptor) and open them in new tabs rather than following them in the same tab

    await page.setRequestInterception(true);
    page.on('request', async function (request) {
      const url = request.url();
      if (url !== REDIRECTION_URL) {
        return request.continue();
      }
      await request.respond({
        contentType: 'text/html',
        status: 304,
        body: '<body></body>',
      });
      const newPage = await browser.newPage();
      await newPage.goto(url, { waitUntil: 'domcontentloaded', timeout: 0 });
      // ...
      await newPage.close();
    });

  • Intercept page response

    page.on('response', async (response) => {
      if (response.url() === RESPONSE_URL) {
        if (response.status() === 200) {
          // ...
        }
        // ...
      }
    });

Boilerplate

Here is the link to the boilerplate I use for the development.