docs(sveltekit): re-introduce speed insights (#9988)

examples/sveltekit-1/.eslintrc.cjs

@@ -1,11 +1,10 @@
 module.exports = {
 	root: true,
-	extends: ['eslint:recommended', 'prettier'],
-	plugins: ['svelte3'],
-	overrides: [{ files: ['*.svelte'], processor: 'svelte3/svelte3' }],
+	extends: ['eslint:recommended', 'plugin:svelte/recommended', 'prettier'],
 	parserOptions: {
 		sourceType: 'module',
-		ecmaVersion: 2020
+		ecmaVersion: 2020,
+		extraFileExtensions: ['.svelte']
 	},
 	env: {
 		browser: true,

examples/sveltekit-1/.npmrc

@@ -1 +1,2 @@
 engine-strict=true
+resolution-mode=highest

examples/sveltekit-1/README.md

@@ -1,18 +1,12 @@
-# create-svelte
+# SvelteKit Demo app
 
-Everything you need to build a Svelte project, powered by [`create-svelte`](https://github.com/sveltejs/kit/tree/master/packages/create-svelte).
+The official demo app for SvelteKit, hosted on Vercel.
 
-## Creating a project
+## Deploy Your Own
 
-If you're seeing this, you've probably already done this step. Congrats!
+[![Deploy with Vercel](https://vercel.com/button)](https://vercel.com/new/clone?repository-url=https%3A%2F%2Fgithub.com%2Fvercel%2Fvercel%2Ftree%2Fmain%2Fexamples%2Fsveltekit-1&project-name=sveltekit-vercel&repository-name=sveltekit-vercel&demo-title=SvelteKit%20%2B%20Vercel&demo-url=https%3A%2F%2Fsveltekit-template.vercel.app%2F)
 
-```bash
-# create a new project in the current directory
-npm create svelte@latest
-
-# create a new project in my-app
-npm create svelte@latest my-app
-```
+_Live Example: https://sveltekit-template.vercel.app_
 
 ## Developing
 
@@ -35,4 +29,8 @@ npm run build
 
 You can preview the production build with `npm run preview`.
 
-> To deploy your app, you may need to install an [adapter](https://kit.svelte.dev/docs/adapters) for your target environment.
+## Speed Insights
+
+Once deployed on Vercel, you can benefit from [Speed Insights](https://vercel.com/docs/concepts/speed-insights) simply by navigating to Vercel's dashboard, clicking on the 'Speed Insights' tab, and enabling the product.
+
+You will get data once your application will be re-deployed and will receive visitors.

examples/sveltekit-1/package.json

@@ -16,19 +16,20 @@
 		"@fontsource/fira-mono": "^4.5.10",
 		"@neoconfetti/svelte": "^1.0.0",
 		"@playwright/test": "^1.28.1",
-		"@sveltejs/adapter-vercel": "^1.0.0",
-		"@sveltejs/kit": "^1.0.0",
+		"@sveltejs/adapter-vercel": "^3.0.0",
+		"@sveltejs/kit": "^1.5.0",
 		"@types/cookie": "^0.5.1",
 		"eslint": "^8.28.0",
 		"eslint-config-prettier": "^8.5.0",
-		"eslint-plugin-svelte3": "^4.0.0",
+		"eslint-plugin-svelte": "^2.26.0",
 		"prettier": "^2.8.0",
 		"prettier-plugin-svelte": "^2.8.1",
 		"svelte": "^3.54.0",
-		"svelte-check": "^2.9.2",
-		"typescript": "^4.9.3",
-		"vite": "^4.0.0",
-		"vitest": "^0.25.3"
+		"svelte-check": "^3.0.1",
+		"typescript": "^5.0.0",
+		"vite": "^4.3.0",
+		"vitest": "^0.25.3",
+		"web-vitals": "^3.3.1"
 	},
 	"type": "module"
 }

examples/sveltekit-1/playwright.config.js

@@ -4,7 +4,8 @@ const config = {
 		command: 'npm run build && npm run preview',
 		port: 4173
 	},
-	testDir: 'tests'
+	testDir: 'tests',
+	testMatch: /(.+\.)?(test|spec)\.[jt]s/
 };
 
 export default config;

examples/sveltekit-1/src/app.d.ts

@@ -1,9 +1,12 @@
 // See https://kit.svelte.dev/docs/types#app
 // for information about these interfaces
-// and what to do when importing types
-declare namespace App {
-	// interface Error {}
-	// interface Locals {}
-	// interface PageData {}
-	// interface Platform {}
+declare global {
+	namespace App {
+		// interface Error {}
+		// interface Locals {}
+		// interface PageData {}
+		// interface Platform {}
+	}
 }
+
+export {};

examples/sveltekit-1/src/lib/vitals.js

@@ -0,0 +1,63 @@
+import { onCLS, onFCP, onFID, onLCP, onTTFB } from 'web-vitals';
+
+const vitalsUrl = 'https://vitals.vercel-analytics.com/v1/vitals';
+
+function getConnectionSpeed() {
+	// @ts-ignore
+	return navigator?.connection?.effectiveType ?? '';
+}
+
+/**
+ * @param {import("web-vitals").Metric} metric
+ * @param {{ params: { [s: string]: any; } | ArrayLike<any>; path: string; analyticsId: string; debug: boolean; }} options
+ */
+function sendToAnalytics(metric, options) {
+	const page = Object.entries(options.params).reduce(
+		(acc, [key, value]) => acc.replace(value, `[${key}]`),
+		options.path
+	);
+
+	const body = {
+		dsn: options.analyticsId,
+		id: metric.id,
+		page,
+		href: location.href,
+		event_name: metric.name,
+		value: metric.value.toString(),
+		speed: getConnectionSpeed()
+	};
+
+	if (options.debug) {
+		console.log('[Web Vitals]', metric.name, JSON.stringify(body, null, 2));
+	}
+
+	const blob = new Blob([new URLSearchParams(body).toString()], {
+		// This content type is necessary for `sendBeacon`
+		type: 'application/x-www-form-urlencoded'
+	});
+	if (navigator.sendBeacon) {
+		navigator.sendBeacon(vitalsUrl, blob);
+	} else
+		fetch(vitalsUrl, {
+			body: blob,
+			method: 'POST',
+			credentials: 'omit',
+			keepalive: true
+		});
+}
+
+/**
+ * @param {any} options
+ */
+export function webVitals(options) {
+	try {
+		console.log(`[Web Vitals] for page ${options.path}`);
+		onFID((metric) => sendToAnalytics(metric, options));
+		onTTFB((metric) => sendToAnalytics(metric, options));
+		onLCP((metric) => sendToAnalytics(metric, options));
+		onCLS((metric) => sendToAnalytics(metric, options));
+		onFCP((metric) => sendToAnalytics(metric, options));
+	} catch (err) {
+		console.error(`[Web Vitals] for page ${options.path}`, err);
+	}
+}

examples/sveltekit-1/src/routes/+layout.server.js

@@ -0,0 +1,6 @@
+import { env } from '$env/dynamic/private';
+
+/** @type {import('./$types').LayoutServerLoad} */
+export function load() {
+	return { analyticsId: env.VERCEL_ANALYTICS_ID };
+}

examples/sveltekit-1/src/routes/+layout.svelte

@@ -1,6 +1,20 @@
 <script>
+	import { browser } from '$app/environment';
+	import { page } from '$app/stores';
+	import { webVitals } from '$lib/vitals';
 	import Header from './Header.svelte';
 	import './styles.css';
+
+	/** @type {import('./$types').LayoutServerData} */
+	export let data;
+
+	$: if (browser && data?.analyticsId) {
+		webVitals({
+			path: $page.url.pathname,
+			params: $page.params,
+			analyticsId: data.analyticsId
+		});
+	}
 </script>
 
 <div class="app">

examples/sveltekit-1/src/routes/sverdle/+page.svelte

@@ -107,11 +107,11 @@
 	<a class="how-to-play" href="/sverdle/how-to-play">How to play</a>
 
 	<div class="grid" class:playing={!won} class:bad-guess={form?.badGuess}>
-		{#each Array(6) as _, row}
+		{#each Array.from(Array(6).keys()) as row (row)}
 			{@const current = row === i}
 			<h2 class="visually-hidden">Row {row + 1}</h2>
 			<div class="row" class:current>
-				{#each Array(5) as _, column}
+				{#each Array.from(Array(5).keys()) as column (column)}
 					{@const answer = data.answers[row]?.[column]}
 					{@const value = data.guesses[row]?.[column] ?? ''}
 					{@const selected = current && column === data.guesses[row].length}

examples/sveltekit-1/tests/test.js

@@ -2,5 +2,5 @@ import { expect, test } from '@playwright/test';
 
 test('about page has expected h1', async ({ page }) => {
 	await page.goto('/about');
-	expect(await page.textContent('h1')).toBe('About this app');
+	await expect(page.getByRole('heading', { name: 'About this app' })).toBeVisible();
 });

examples/sveltekit-1/vite.config.js

@@ -1,11 +1,9 @@
 import { sveltekit } from '@sveltejs/kit/vite';
+import { defineConfig } from 'vitest/config';
 
-/** @type {import('vite').UserConfig} */
-const config = {
+export default defineConfig({
 	plugins: [sveltekit()],
 	test: {
 		include: ['src/**/*.{test,spec}.{js,ts}']
 	}
-};
-
-export default config;
+});