feat(vercel): Add support for analytics (Audiences & Web Vitals) (#6148)

* feat(intergration/vercel): add vercel analytics support

* docs(intergration/vercel): add vercel analytics prop

* docs(intergration/vercel): bump version to 3.1.0

* Update packages/integrations/vercel/README.md

Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>

* docs(intergration/vercel): add file name for example

* feat(intergration/vercel): convert analytics to ts and support in edge

* docs(intergration/vercel): move file names to code blocks as comments

* fix(intergration/vercel): remove unused import

* feat(intergration/vercel): add analytics support to static mode

* chore(intergration/vercel): revert version change

* style(intergration/vercel): add a blank line after astro import

* chore(intergration/vercel): generate file by changeset

* Update .changeset/eighty-bobcats-deliver.md

Co-authored-by: Chris Swithinbank <swithinbank@gmail.com>

* Update packages/integrations/vercel/README.md

Co-authored-by: Chris Swithinbank <swithinbank@gmail.com>

* Update packages/integrations/vercel/src/analytics.ts

Co-authored-by: Chris Swithinbank <swithinbank@gmail.com>

* chore(intergration/vercel): simplify analytics script

---------

Co-authored-by: Sarah Rainsberger <sarah@rainsberger.ca>
Co-authored-by: Nate Moore <natemoo-re@users.noreply.github.com>
Co-authored-by: Chris Swithinbank <swithinbank@gmail.com>

8 files changed, 137 insertions, 7 deletions

diff --git a/.changeset/eighty-bobcats-deliver.md b/.changeset/eighty-bobcats-deliver.md
new file mode 100644
index 000000000..064719c78
--- /dev/null
+++ b/.changeset/eighty-bobcats-deliver.md
@@ -0,0 +1,5 @@
+---
+'@astrojs/vercel': minor
+---
+
+Add vercel analytics support
diff --git a/packages/integrations/vercel/README.md b/packages/integrations/vercel/README.md
index db89064c8..64bd66a89 100644
--- a/packages/integrations/vercel/README.md
+++ b/packages/integrations/vercel/README.md
@@ -87,6 +87,26 @@ vercel deploy --prebuilt
 
 To configure this adapter, pass an object to the `vercel()` function call in `astro.config.mjs`:
 
+### analytics
+
+> **Type:** `boolean`
+> **Available for:** Serverless, Edge, Static
+
+You can enable [Vercel Analytics](https://vercel.com/analytics) (including Web Vitals and Audiences) by setting `analytics: true`. This will inject Vercel’s tracking scripts into all your pages.
+
+```js
+// astro.config.mjs
+import { defineConfig } from 'astro/config';
+import vercel from '@astrojs/vercel/serverless';
+
+export default defineConfig({
+  output: 'server',
+  adapter: vercel({
+    analytics: true
+  })
+});
+```
+
 ### includeFiles
 
 > **Type:** `string[]`
@@ -95,6 +115,7 @@ To configure this adapter, pass an object to the `vercel()` function call in `as
 Use this property to force files to be bundled with your function. This is helpful when you notice missing files.
 
 ```js
+// astro.config.mjs
 import { defineConfig } from 'astro/config';
 import vercel from '@astrojs/vercel/serverless';
 
@@ -109,7 +130,6 @@ export default defineConfig({
 > **Note**
 > When building for the Edge, all the dependencies get bundled in a single file to save space. **No extra file will be bundled**. So, if you _need_ some file inside the function, you have to specify it in `includeFiles`.
 
-
 ### excludeFiles
 
 > **Type:** `string[]`
@@ -118,6 +138,7 @@ export default defineConfig({
 Use this property to exclude any files from the bundling process that would otherwise be included.
 
 ```js
+// astro.config.mjs
 import { defineConfig } from 'astro/config';
 import vercel from '@astrojs/vercel/serverless';
 
diff --git a/packages/integrations/vercel/package.json b/packages/integrations/vercel/package.json
index 95908173b..8332c64dd 100644
--- a/packages/integrations/vercel/package.json
+++ b/packages/integrations/vercel/package.json
@@ -22,6 +22,7 @@
     "./serverless": "./dist/serverless/adapter.js",
     "./serverless/entrypoint": "./dist/serverless/entrypoint.js",
     "./static": "./dist/static/adapter.js",
+    "./analytics": "./dist/analytics.js",
     "./package.json": "./package.json"
   },
   "typesVersions": {
@@ -45,9 +46,11 @@
   },
   "dependencies": {
     "@astrojs/webapi": "^2.0.0",
+    "@vercel/analytics": "^0.1.8",
     "@vercel/nft": "^0.22.1",
     "fast-glob": "^3.2.11",
-    "set-cookie-parser": "^2.5.1"
+    "set-cookie-parser": "^2.5.1",
+    "web-vitals": "^3.1.1"
   },
   "peerDependencies": {
     "astro": "workspace:^2.0.8"
diff --git a/packages/integrations/vercel/src/analytics.ts b/packages/integrations/vercel/src/analytics.ts
new file mode 100644
index 000000000..95dee83e3
--- /dev/null
+++ b/packages/integrations/vercel/src/analytics.ts
@@ -0,0 +1,64 @@
+import { inject } from '@vercel/analytics';
+import type { Metric } from 'web-vitals';
+import { getCLS, getFCP, getFID, getLCP, getTTFB } from 'web-vitals';
+
+const vitalsUrl = 'https://vitals.vercel-analytics.com/v1/vitals';
+
+type Options = { path: string; analyticsId: string };
+
+const getConnectionSpeed = () => {
+	return 'connection' in navigator &&
+		navigator['connection'] &&
+		'effectiveType' in (navigator['connection'] as unknown as { effectiveType: string })
+		? (navigator['connection'] as unknown as { effectiveType: string })['effectiveType']
+		: '';
+};
+
+const sendToAnalytics = (metric: Metric, options: Options) => {
+	const body = {
+		dsn: options.analyticsId,
+		id: metric.id,
+		page: options.path,
+		href: location.href,
+		event_name: metric.name,
+		value: metric.value.toString(),
+		speed: getConnectionSpeed(),
+	};
+	const blob = new Blob([new URLSearchParams(body).toString()], {
+		type: 'application/x-www-form-urlencoded',
+	});
+	if (navigator.sendBeacon) {
+		navigator.sendBeacon(vitalsUrl, blob);
+	} else
+		fetch(vitalsUrl, {
+			body: blob,
+			method: 'POST',
+			credentials: 'omit',
+			keepalive: true,
+		});
+};
+
+function webVitals() {
+	const analyticsId = (import.meta as any).env.PUBLIC_VERCEL_ANALYTICS_ID;
+	if (!analyticsId) {
+		console.error('[Analytics] VERCEL_ANALYTICS_ID not found');
+		return;
+	}
+	const options: Options = { path: window.location.pathname, analyticsId };
+	try {
+		getFID((metric) => sendToAnalytics(metric, options));
+		getTTFB((metric) => sendToAnalytics(metric, options));
+		getLCP((metric) => sendToAnalytics(metric, options));
+		getCLS((metric) => sendToAnalytics(metric, options));
+		getFCP((metric) => sendToAnalytics(metric, options));
+	} catch (err) {
+		console.error('[Analytics]', err);
+	}
+}
+
+const mode = (import.meta as any).env.MODE as 'development' | 'production';
+
+inject({ mode });
+if (mode === 'production') {
+	webVitals();
+}
diff --git a/packages/integrations/vercel/src/edge/adapter.ts b/packages/integrations/vercel/src/edge/adapter.ts
index 3f38a074e..3e9eb5929 100644
--- a/packages/integrations/vercel/src/edge/adapter.ts
+++ b/packages/integrations/vercel/src/edge/adapter.ts
@@ -1,4 +1,5 @@
 import type { AstroAdapter, AstroConfig, AstroIntegration } from 'astro';
+
 import esbuild from 'esbuild';
 import { relative as relativePath } from 'node:path';
 import { fileURLToPath } from 'node:url';
@@ -24,9 +25,13 @@ function getAdapter(): AstroAdapter {
 
 export interface VercelEdgeConfig {
 	includeFiles?: string[];
+	analytics?: boolean;
 }
 
-export default function vercelEdge({ includeFiles = [] }: VercelEdgeConfig = {}): AstroIntegration {
+export default function vercelEdge({
+	includeFiles = [],
+	analytics,
+}: VercelEdgeConfig = {}): AstroIntegration {
 	let _config: AstroConfig;
 	let buildTempFolder: URL;
 	let functionFolder: URL;
@@ -35,7 +40,10 @@ export default function vercelEdge({ includeFiles = [] }: VercelEdgeConfig = {})
 	return {
 		name: PACKAGE_NAME,
 		hooks: {
-			'astro:config:setup': ({ config, updateConfig }) => {
+			'astro:config:setup': ({ config, updateConfig, injectScript }) => {
+				if (analytics) {
+					injectScript('page', 'import "@astrojs/vercel/analytics"');
+				}
 				const outDir = getVercelOutput(config.root);
 				updateConfig({
 					outDir,
diff --git a/packages/integrations/vercel/src/serverless/adapter.ts b/packages/integrations/vercel/src/serverless/adapter.ts
index 3ff5eb3e5..884510516 100644
--- a/packages/integrations/vercel/src/serverless/adapter.ts
+++ b/packages/integrations/vercel/src/serverless/adapter.ts
@@ -19,11 +19,13 @@ function getAdapter(): AstroAdapter {
 export interface VercelServerlessConfig {
 	includeFiles?: string[];
 	excludeFiles?: string[];
+	analytics?: boolean;
 }
 
 export default function vercelServerless({
 	includeFiles,
 	excludeFiles,
+	analytics,
 }: VercelServerlessConfig = {}): AstroIntegration {
 	let _config: AstroConfig;
 	let buildTempFolder: URL;
@@ -33,7 +35,10 @@ export default function vercelServerless({
 	return {
 		name: PACKAGE_NAME,
 		hooks: {
-			'astro:config:setup': ({ config, updateConfig }) => {
+			'astro:config:setup': ({ config, updateConfig, injectScript }) => {
+				if (analytics) {
+					injectScript('page', 'import "@astrojs/vercel/analytics"');
+				}
 				const outDir = getVercelOutput(config.root);
 				updateConfig({
 					outDir,
diff --git a/packages/integrations/vercel/src/static/adapter.ts b/packages/integrations/vercel/src/static/adapter.ts
index 597c93626..28da5d4da 100644
--- a/packages/integrations/vercel/src/static/adapter.ts
+++ b/packages/integrations/vercel/src/static/adapter.ts
@@ -9,13 +9,20 @@ function getAdapter(): AstroAdapter {
 	return { name: PACKAGE_NAME };
 }
 
-export default function vercelStatic(): AstroIntegration {
+export interface VercelStaticConfig {
+	analytics?: boolean;
+}
+
+export default function vercelStatic({ analytics }: VercelStaticConfig = {}): AstroIntegration {
 	let _config: AstroConfig;
 
 	return {
 		name: '@astrojs/vercel',
 		hooks: {
-			'astro:config:setup': ({ config }) => {
+			'astro:config:setup': ({ config, injectScript }) => {
+				if (analytics) {
+					injectScript('page', 'import "@astrojs/vercel/analytics"');
+				}
 				config.outDir = new URL('./static/', getVercelOutput(config.root));
 				config.build.format = 'directory';
 			},
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 73a3bfe82..cd3ab9c87 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -3335,6 +3335,7 @@ importers:
     specifiers:
       '@astrojs/webapi': ^2.0.0
       '@types/set-cookie-parser': ^2.4.2
+      '@vercel/analytics': ^0.1.8
       '@vercel/nft': ^0.22.1
       astro: workspace:*
       astro-scripts: workspace:*
@@ -3342,11 +3343,14 @@ importers:
       fast-glob: ^3.2.11
       mocha: ^9.2.2
       set-cookie-parser: ^2.5.1
+      web-vitals: ^3.1.1
     dependencies:
       '@astrojs/webapi': link:../../webapi
+      '@vercel/analytics': 0.1.8
       '@vercel/nft': 0.22.6
       fast-glob: 3.2.12
       set-cookie-parser: 2.5.1
+      web-vitals: 3.1.1
     devDependencies:
       '@types/set-cookie-parser': 2.4.2
       astro: link:../../astro
@@ -7623,6 +7627,15 @@ packages:
       '@unocss/scope': 0.15.6
     dev: false
 
+  /@vercel/analytics/0.1.8:
+    resolution: {integrity: sha512-PQrOI8BJ9qUiVJuQfnKiJd15eDjDJH9TBKsNeMrtelT4NAk7d9mBVz1CoZkvoFnHQ0OW7Xnqmr1F2nScfAnznQ==}
+    peerDependencies:
+      react: ^16.8||^17||^18
+    peerDependenciesMeta:
+      react:
+        optional: true
+    dev: false
+
   /@vercel/nft/0.22.6:
     resolution: {integrity: sha512-gTsFnnT4mGxodr4AUlW3/urY+8JKKB452LwF3m477RFUJTAaDmcz2JqFuInzvdybYIeyIv1sSONEJxsxnbQ5JQ==}
     engines: {node: '>=14'}
@@ -15398,6 +15411,10 @@ packages:
     resolution: {integrity: sha512-e0MO3wdXWKrLbL0DgGnUV7WHVuw9OUvL4hjgnPkIeEvESk74gAITi5G606JtZPp39cd8HA9VQzCIvA49LpPN5Q==}
     engines: {node: '>= 8'}
 
+  /web-vitals/3.1.1:
+    resolution: {integrity: sha512-qvllU+ZeQChqzBhZ1oyXmWsjJ8a2jHYpH8AMaVuf29yscOPZfTQTjQFRX6+eADTdsDE8IanOZ0cetweHMs8/2A==}
+    dev: false
+
   /webidl-conversions/3.0.1:
     resolution: {integrity: sha512-2JAn3z8AR6rjK8Sm8orRC0h/bcl/DqL7tRPdGZ4I1CjdF+EaMLmYxBHyXuKL849eucPFhvBoxMsflfOb8kxaeQ==}