Save a dynamically rendered page with Chrome Headless browser

render.js

// Needs a running Chrome Headless, eg:
// /Applications/Google\ Chrome\ Canary.app/Contents/MacOS/Google\ Chrome\ Canary  --headless --remote-debugging-port=9222 https://chromium.org
// Run with node, eg `node render.js output.html`
  
const CDP = require('chrome-remote-interface');
const fs = require('fs')

CDP((client) => {
  // Extract used DevTools domains.
  const {Page, Runtime} = client;

  // Enable events on domains we are interested in.
  Promise.all([
    Page.enable()
  ]).then(() => {
    // bootstrap.html should load all js and css etc.
    return Page.navigate({url: 'file://' + process.cwd() + '/render/bootstrap.html'});
  });

  // Evaluate outerHTML after page has loaded.
  Page.loadEventFired(() => {
    Runtime.evaluate({expression: 'document.documentElement.outerHTML'}).then((result) => {
      fs.writeFileSync(process.argv[2],result.result.value)
      client.close();
    });
  });
}).on('error', (err) => {
  console.error('Cannot connect to browser:', err);
});

awesome script, thank you!

I had to fire up a local web server to get it working, but other than that, it's working great!