Docs: add PostHog analytics

docs/.vitepress/config.ts

@@ -93,6 +93,8 @@ export default defineConfig({
     outline: { level: [2, 3] },
   },
   vite: {
+    // the PostHog variables on Vercel use the NEXT_PUBLIC_ prefix
+    envPrefix: ['VITE_', 'NEXT_PUBLIC_'],
     server: { fs: { allow: ['..'] } },
     ssr: { external: ['clipper-lib', 'svgo'] },
     plugins: [

docs/.vitepress/theme/index.ts

@@ -11,5 +11,18 @@ export default {
     app.component('IconGrid', IconGrid);
     app.component('IconPage', IconPage);
     app.component('HomeShowcase', HomeShowcase);
+
+    // Analytics: browser only, and only when a key is configured (so local dev and forks stay silent).
+    const key = import.meta.env.NEXT_PUBLIC_POSTHOG_KEY as string | undefined;
+    if (!import.meta.env.SSR && key) {
+      void import('posthog-js').then(({ default: posthog }) => {
+        posthog.init(key, {
+          api_host: (import.meta.env.NEXT_PUBLIC_POSTHOG_HOST as string | undefined) ?? 'https://eu.i.posthog.com',
+          // the `defaults` snapshot also turns on pageviews for client-side route changes
+          defaults: '2025-05-24',
+          person_profiles: 'identified_only',
+        });
+      });
+    }
   },
 } satisfies Theme;

docs/package.json

@@ -8,6 +8,7 @@
     "preview": "vitepress preview"
   },
   "devDependencies": {
+    "posthog-js": "^1.434.0",
     "svgo": "^4.1.0",
     "vitepress": "^1.6.4",
     "vitepress-plugin-llms": "1.14.0",