Move beforeSend out of config

packages/integrations/vercel/README.md

@@ -92,7 +92,7 @@ To configure this adapter, pass an object to the `vercel()` function call in `as
 **Added in:** `@astrojs/vercel@3.8.0`
 
 You can enable [Vercel Web Analytics](https://vercel.com/docs/concepts/analytics) by setting `webAnalytics: { enabled: true }`. This will inject Vercel’s tracking scripts into all of your pages.
-Alternatively, you can pass all [available configuration options](https://vercel.com/docs/concepts/analytics/package) via the `config` property inside `webAnalytics`.
+Alternatively, you can also pass [configuration options](https://vercel.com/docs/concepts/analytics/package) (except functions like `beforeSend`) via the `config` property inside `webAnalytics`.
 
 ```js
 // astro.config.mjs
@@ -104,20 +104,32 @@ export default defineConfig({
   adapter: vercel({
     webAnalytics: {
       enabled: true,
-      config: {
+    },
-        beforeSend: (event) => {
-          // Ignore all events that have a `/private` inside the URL
-          if (event.url.includes('/private')) {
-            return null;
-          }
-          return event;
-        }
-      }
-    }
   }),
 });
 ```
 
+#### `beforeSend`
+
+Since functions can't be passed down via `astro.config.mjs`, you need to export the `beforeSend` function in a separate file inside your root called `vercel-web-analytics.ts`.
+If you're not using TypeScript, you can define the function inside `vercel-web-analytics.js`.
+
+```js
+// vercel-web-analytics.ts
+import type { VercelWebAnalyticsBeforeSend } from '@astrojs/vercel';
+
+export const beforeSend: VercelWebAnalyticsBeforeSend = (event) => {
+    // Ignore all events that have a `/private` inside the URL
+    if (event.url.includes('/private')) {
+      return null;
+    }
+    return event;
+  }
+}
+```
+
+````js
+
 ### Speed Insights
 You can enable [Vercel Speed Insights](https://vercel.com/docs/concepts/speed-insights) by setting `speedInsights: { enabled: true }`. This will collect and send Web Vital data to Vercel.
 
@@ -138,7 +150,7 @@ export default defineConfig({
     }
   }),
 });
-```
+````
 
 ### imagesConfig
 

packages/integrations/vercel/src/edge/adapter.ts

@@ -55,14 +55,17 @@ export default function vercelEdge({
 	return {
 		name: PACKAGE_NAME,
 		hooks: {
-			'astro:config:setup': ({ command, config, updateConfig, injectScript }) => {
+			'astro:config:setup': async ({ command, config, updateConfig, injectScript }) => {
 				if (webAnalytics?.enabled) {
 					injectScript(
 						'page',
-						getInjectableWebAnalyticsContent({
+						await getInjectableWebAnalyticsContent(
-							...webAnalytics.config,
+							{
-							mode: command === 'dev' ? 'development' : 'production',
+								...webAnalytics.config,
-						})
+								mode: command === 'dev' ? 'development' : 'production',
+							},
+							config.root
+						)
 					);
 				}
 				if (command === 'build' && speedInsights?.enabled) {

packages/integrations/vercel/src/lib/web-analytics.ts

@@ -1,15 +1,56 @@
 import type { AnalyticsProps } from '@vercel/analytics';
+import { fileURLToPath } from 'url';
 
 export type VercelWebAnalyticsConfig = {
 	enabled: boolean;
-	config?: AnalyticsProps;
+	config?: Omit<AnalyticsProps, 'beforeSend'>;
 };
 
-export function getInjectableWebAnalyticsContent(config?: AnalyticsProps) {
+async function getWebAnalyticsFunctions(root: URL) {
+	try {
+		const files = await Promise.all([
+			import(/* @vite-ignore */ fileURLToPath(new URL('./vercel-web-analytics.ts', root))).catch(
+				() => undefined
+			),
+			import(/* @vite-ignore */ fileURLToPath(new URL('./vercel-web-analytics.js', root))).catch(
+				() => undefined
+			),
+		]);
+
+		const functions = files[0] || files[1];
+
+		if (functions?.default) {
+			if (typeof functions.default.beforeSend !== 'function') {
+				throw new Error(
+					`@astrojs/vercel: ./vercel-web-analytics.js should export a \`beforeSend\` function.`
+				);
+			}
+
+			return {
+				beforeSend: functions.default.beforeSend,
+			};
+		}
+
+		return {
+			beforeSend: undefined,
+		};
+	} catch (e) {
+		return {
+			beforeSend: undefined,
+		};
+	}
+}
+
+export async function getInjectableWebAnalyticsContent(
+	config: Omit<AnalyticsProps, 'beforeSend'> | undefined,
+	root: URL
+) {
+	const { beforeSend } = await getWebAnalyticsFunctions(root);
+
 	return `import { inject } from '@vercel/analytics';
 		inject({
 			mode: ${config?.mode},
-			beforeSend: ${config?.beforeSend},
+			beforeSend: ${beforeSend},
 			debug: ${config?.debug}
 		});`;
 }

packages/integrations/vercel/src/serverless/adapter.ts

@@ -116,14 +116,17 @@ export default function vercelServerless({
 	return {
 		name: PACKAGE_NAME,
 		hooks: {
-			'astro:config:setup': ({ command, config, updateConfig, injectScript }) => {
+			'astro:config:setup': async ({ command, config, updateConfig, injectScript }) => {
 				if (webAnalytics?.enabled) {
 					injectScript(
 						'page',
-						getInjectableWebAnalyticsContent({
+						await getInjectableWebAnalyticsContent(
-							...webAnalytics.config,
+							{
-							mode: command === 'dev' ? 'development' : 'production',
+								...webAnalytics.config,
-						})
+								mode: command === 'dev' ? 'development' : 'production',
+							},
+							config.root
+						)
 					);
 				}
 				if (command === 'build' && speedInsights?.enabled) {

packages/integrations/vercel/src/static/adapter.ts

@@ -37,14 +37,17 @@ export default function vercelStatic({
 	return {
 		name: '@astrojs/vercel',
 		hooks: {
-			'astro:config:setup': ({ command, config, injectScript, updateConfig }) => {
+			'astro:config:setup': async ({ command, config, injectScript, updateConfig }) => {
 				if (webAnalytics?.enabled) {
 					injectScript(
 						'page',
-						getInjectableWebAnalyticsContent({
+						await getInjectableWebAnalyticsContent(
-							...webAnalytics.config,
+							{
-							mode: command === 'dev' ? 'development' : 'production',
+								...webAnalytics.config,
-						})
+								mode: command === 'dev' ? 'development' : 'production',
+							},
+							config.root
+						)
 					);
 				}
 				if (command === 'build' && speedInsights?.enabled) {

packages/integrations/vercel/src/types.d.ts

@@ -0,0 +1,3 @@
+import type { AnalyticsProps } from '@vercel/analytics';
+
+export type VercelWebAnalyticsBeforeSend = AnalyticsProps['beforeSend'];