How to set max viewport in Puppeteer?

Question

When I run a new page, I must specify size of the viewport using the setViewport function:

await page.setViewport({
    width: 1920,
    height: 108         


        

Answer 1

You can pass the --window-size flag as an argument to puppeteer.launch() to change the window size to your desired width and height.

Then you can call the Chrome Devtools Protocol method Emulation.clearDeviceMetricsOverride to clear the overridden device metrics (including the default 800 x 600 viewport).

This will cause the viewport to match the window size (when taking screenshots, etc).

const browser = await puppeteer.launch({
  args: [
    '--window-size=1920,1080',
  ],
});

const page = await browser.newPage();

await page._client.send('Emulation.clearDeviceMetricsOverride');

await page.screenshot({
  path: 'example.png', // Image Dimensions : 1920 x 1080
});

Note: page.viewport() will still return { width: 800, height: 600 }, and the only way to reliably change the values of these properties is to use page.setViewport().

See the complete example below:

'use strict';

const puppeteer = require('puppeteer');

(async () => {
  /* ============================================================
      Prerequisite: Set Window size
  ============================================================ */

  const browser = await puppeteer.launch({
    args : [
      '--window-size=1920,1080',
    ],
  });

  const page = await browser.newPage();

  await page.goto('https://www.example.com/');

  /* ============================================================
      Case 1: Default Viewport
  ============================================================ */

  console.log('Case 1 - Width  :', page.viewport().width);  // Width  : 800
  console.log('Case 1 - Height :', page.viewport().height); // Height : 600

  await page.screenshot({
    path: 'image-1.png', // Image Dimensions : 800 x 600
  });

  /* ============================================================
      Case 2: Clear Overridden Device Metrics
  ============================================================ */

  await page._client.send('Emulation.clearDeviceMetricsOverride');

  console.log('Case 2 - Width  :', page.viewport().width);  // Width  : 800
  console.log('Case 2 - Height :', page.viewport().height); // Height : 600

  await page.screenshot({
    path: 'image-2.png', // Image Dimensions : 1920 x 1080
  });

  /* ============================================================
      Case 3: Manually Set Viewport
  ============================================================ */

  await page.setViewport({
    width: 1920,
    height: 1080,
  });

  console.log('Case 3 - Width  :', page.viewport().width);  // Width  : 1920
  console.log('Case 3 - Height :', page.viewport().height); // Height : 1080

  await page.screenshot({
    path: 'image-3.png', // Image Dimensions : 1920 x 1080
  });

  /* ============================================================
      Case 4: Revert Back to Default Viewport
  ============================================================ */

  await page.setViewport({
      width: 800,
      height: 600,
  });

  console.log('Case 4 - Width  :', page.viewport().width);  // Width  : 800
  console.log('Case 4 - Height :', page.viewport().height); // Height : 600

  await page.screenshot({
    path: 'image-4.png', // Image Dimensions : 800 x 600
  });

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