screenshot.js

const viewportWidth = 1200;
const viewportHeight = 900;
const argv = process.argv;

var path = require('path');
const puppeteer = require('puppeteer');

if (argv.length < 3) {
  console.error('Usage: node ' + path.basename(argv[1]) + ' <path> <url>');
  process.exit(1);
}

(async () => {
  const browser = await puppeteer.launch();
  const page = await browser.newPage();
  page.setViewport({width: viewportWidth, height: viewportHeight});
  await page.goto(argv[3]);
  page.evaluate(_ => {
    window.scrollBy(0, window.innerHeight);
  });
  await page.screenshot({
    path: argv[2],
    fullPage: true
  });
  await browser.close();
})();