How to maximise Screen use in Pupeteer ( non-headless )

You probably would want to set a certain screen size, which any real browser has:

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  await page.setViewport({ width: 1366, height: 768});
  await page.goto('https://example.com', {waitUntil: 'networkidle2'});
  await page.screenshot({path: 'example.png'});

  browser.close();
})();

const puppeteer = require('puppeteer-core');

(async () => {
  const browser = await puppeteer.launch({
    headless: false,
    defaultViewport: null,
  });

  const pages = await browser.pages();
  const page = pages[0];
  await page.goto('https://google.com');
})();

Source: https://github.com/GoogleChrome/puppeteer/issues/3688#issuecomment-453218745

you can user options in launch

const puppeteer = require('puppeteer');

(async () => {
  const browser = await puppeteer.launch({
    args:[
       '--start-maximized' // you can also use '--start-fullscreen'
    ]
    });

  const page = await browser.newPage();
  await page.setViewport({ width: 1366, height: 768});
  await page.goto('https://example.com', {waitUntil: 'networkidle2'});
  await page.screenshot({path: 'example.png'});

  browser.close();
})();