screenshot a website with puppeteer (headless chrome)

screenshot.js

const puppeteer = require('puppeteer');
const argv = require('yargs').argv

if (argv.url && argv.filename){
  (async () => {
    const browser = await puppeteer.launch({headless: true, ignoreHTTPSErrors: true});
    process.on("unhandledRejection", (reason, p) => {
      console.error("Unhandled Rejection at: Promise", p, "reason:", reason);
      browser.close();
    });
    const page = await browser.newPage();
    page.on('error', function(msg){
      console.log(msg);
    })
    page.on('pageerror', function(msg){
      console.log(msg);
    })
    await page.goto(argv.url, {timeout: 10000})
    await page.waitForSelector('body');
    await page.screenshot({path: argv.filename});
    await browser.close();
    
  })();
} else {
  console.log("Try screen --url=https://www.example.com --filename=foo.png");
}