Addy Osmani addyosmani

git log --pretty=format:"* %s" v0.0.8..v0.1.0 > changelog.md

Web Page Usability Matters
PageSpeed Insights w/Lighthouse and Chrome User Experience Report
Data Saver for Chrome on Android - enable and then look at about:flags for Lite Pages and other interventions
web.dev/fast - code-labs and tooling for optimizing performance
Lighthousebot for using Lighthouse in continuous integration
Bundlesize for JavaScript budgets in CI
Start performance budgeting

Working with a React codebase and want to use Preact? Ideally, you should use preact and preact-compat for your dev, prod and test builds. This will enable you to discover any interop bugs early on. If you would prefer to only alias preact and preact-compat in Webpack for production builds (e.g if your preference is using React DevTools and enzyme), make sure to thoroughly test everything works as expected before deploying to your servers.

Workbox runtime caching recipes

Your Service Worker script will need to import in Workbox and initialize it before calling any of the routes documented in this write-up, similar to the below:

importScripts('workbox-sw.prod.v1.3.0.js');
const workbox = new WorkboxSW();

// Placeholder array populated automatically by workboxBuild.injectManifest()

	const loader = new loadScript();
	loader.load([
	'//apis.google.com/js/client:platform.js?onload=startApp',
	'//cdnjs.cloudflare.com/ajax/libs/dropbox.js/0.10.3/dropbox.min.js'
	]).then(({length}) => {
	console.log(`${length} scripts loaded!`);
	});

	[lcp]
	const po = new PerformanceObserver(() => {});
	po.observe({type: 'largest-contentful-paint', buffered: true});
	const lastEntry = po.takeRecords().slice(-1)[0];
	return lastEntry.renderTime \|\| lastEntry.loadTime;

	[cls]
	const po = new PerformanceObserver(() => {});
	po.observe({type: 'layout-shift', buffered: true});
	return po.takeRecords().reduce((val, entry) => val + entry.value, 0);

	const puppeteer = require('puppeteer');

	const Good3G = {
	'offline': false,
	'downloadThroughput': 1.5 * 1024 * 1024 / 8,
	'uploadThroughput': 750 * 1024 / 8,
	'latency': 40
	};

	const phone = puppeteer.KnownDevices['Nexus 5X'];

	<img data-src="unicorn.jpg" loading="lazy" alt=".." class="lazyload"/>

	<script>
	// Select all images with the class "lazyload"
	const images = document.querySelectorAll("img.lazyload");
	// Check if the browser supports the "loading" attribute
	if ('loading' in HTMLImageElement.prototype) {
	// If so, we'll update all <img src> to point to the data-src instead
	images.forEach(img => {
	img.src = img.dataset.src;

	// Examples at https://gist.github.com/bendc/9b05735dfa6966859025#gistcomment-1370485


	// array utils
	// =================================================================================================

	const combine = (...arrays) => [].concat(...arrays);

	const compact = arr => arr.filter(Boolean);