Using lighthouse

lighthouse.js

const fs = require('fs');
const lighthouse = require('lighthouse');
const puppeteer = require('puppeteer');
const DOMAIN = process.env.DOMAIN;

// build report for single url
const buildReport = browser => async url => {
  const data = await lighthouse(
    `${DOMAIN}${url}`,
    {
      port: new URL(browser.wsEndpoint()).port,
      output: 'json',
    },
    {
      extends: 'lighthouse:full',
    }
  );
  const { report: reportJSON } = data;
  const report = JSON.parse(reportJSON);
  const metrics = [
    {
      name: report.categories.performance.title,
      value: report.categories.performance.score,
      desiredSize: 'larger',
    },
    {
      name: report.categories.accessibility.title,
      value: report.categories.accessibility.score,
      desiredSize: 'larger',
    },
    {
      name: report.categories['best-practices'].title,
      value: report.categories['best-practices'].score,
      desiredSize: 'larger',
    },
    {
      name: report.categories.seo.title,
      value: report.categories.seo.score,
      desiredSize: 'larger',
    },
    {
      name: report.categories.pwa.title,
      value: report.categories.pwa.score,
      desiredSize: 'larger',
    },
  ];
  return {
    subject: url,
    metrics: metrics,
  };
};

const urls = [
  '/inloggen',
  '/wachtwoord-herstellen-otp',
  '/lp/service',
  '/send-request-to/ww-tammer',
  '/post-service-request/binnenschilderwerk',
];

(async () => {
  const browser = await puppeteer.launch({
    args: ['--no-sandbox', '--disable-setuid-sandbox', '--headless'],
  });
  const builder = buildReport(browser);
  const report = [];
  for (let url of urls) {
    const metrics = await builder(url);
    report.push(metrics);
  }
  fs.writeFileSync(`./performance.json`, JSON.stringify(report));
  await browser.close();
})();