index.js

const path = require('path');
const puppeteer = require(process.cwd() + "/node_modules/puppeteer");

// Support for pkg
const executablePath =
  process.env.PUPPETEER_EXECUTABLE_PATH ||
  (process.pkg
    ? path.join(
        path.dirname(process.execPath),
        'puppeteer',
        ...puppeteer
          .executablePath()
          .split(path.sep)
          .slice(6), // /snapshot/project/node_modules/puppeteer/.local-chromium
      )
    : puppeteer.executablePath());

if(process.argv.length < 3){
	console.log("You need to supply the URL as parameter: flyscreen <URL>");
	process.exit(0);
}

(async () => {
	// 1. Launch the browser
	const browser = await puppeteer.launch({executablePath, defaultViewport: null});

	// 2. Open a new page
	const page = await browser.newPage();

	try {

		await page.setViewport({
		  width: 400,
		  height: 2000,
		  deviceScaleFactor: 1,
		   // isLandscape: true
		});

  		for (let i = 2; i < process.argv.length; i++) {
			await takeScreen(page, process.argv[i]);
		}

		await page.setViewport({
		  width: 800,
		  height: 2000,
		  deviceScaleFactor: 1,
		});

  		for (let i = 2; i < process.argv.length; i++) {
			await takeScreen(page, process.argv[i]);
		}

		await page.setViewport({
		  width: 1024,
		  height: 2000,
		  deviceScaleFactor: 1,
		});

  		for (let i = 2; i < process.argv.length; i++) {
			await takeScreen(page, process.argv[i]);
		}

		await page.setViewport({
		  width: 2048,
		  height: 2000,
		  deviceScaleFactor: 1,
		});

  		for (let i = 2; i < process.argv.length; i++) {
			await takeScreen(page, process.argv[i]);
		}
	
  		await browser.close();
  		process.exit(0);
  		
	} catch (e) {
  		console.log(e);
  		process.exit(1);
	}
})();

async function takeScreen(page, url){
	// 3. Navigate to URL
	await page.goto(url);

	let resolution = page.viewport().width + 'x' + page.viewport().height;
	console.log(`Resolution: ${resolution}`);
	let path = 'screenshots/' + `screenshot-${url}`.replace(/\//g,".") + resolution + '.png';
	// 4. Take screenshot
	await page.screenshot({path: path});
}