feat: implement segment link tracking, opt-in solution

src/plugins/docusaurus-plugin-segment/index.js

@@ -7,7 +7,10 @@ module.exports = function (context, options) {
         name: 'docusaurus-plugin-segment',
 
         getClientModules() {
-            return [path.resolve(__dirname, './segment')];
+            return [
+                path.resolve(__dirname, './segment'),
+                path.resolve(__dirname, './linkTracking'),
+            ];
         },
 
         injectHtmlTags() {

src/plugins/docusaurus-plugin-segment/linkTracking.js

@@ -0,0 +1,59 @@
+import ExecutionEnvironment from '@docusaurus/ExecutionEnvironment';
+
+// Opt-in link trackers. Currently limited to Trust Center to avoid Segment noise - see https://github.com/apify/apify-docs/issues/2409.
+const LINK_TRACKERS = [
+    {
+        test: (url) => url.hostname === 'trust.apify.com',
+        element: 'trust-center-link',
+    },
+    // Examples for future opt-in:
+    // { test: (url) => !/(^|\.)apify\.com$/.test(url.hostname) } // all outbound
+    // { test: () => true }                                       // all links
+];
+
+let installed = false;
+
+function handleLinkClick(event) {
+    // auxclick fires for all non-primary buttons; only handle middle click (button === 1)
+    if (event.type === 'auxclick' && event.button !== 1) return;
+    if (process.env.NODE_ENV !== 'production' || !window.analytics) return;
+
+    const anchor = event.target.closest('a[href]');
+    if (!anchor) return;
+
+    let url;
+    try {
+        url = new URL(anchor.getAttribute('href'), window.location.href);
+    } catch {
+        return;
+    }
+    if (!/^https?:$/.test(url.protocol)) return;
+
+    const tracker = LINK_TRACKERS.find(({ test }) => test(url));
+    if (!tracker) return;
+
+    const isApifyDomain = /(^|\.)apify\.com$/.test(url.hostname);
+
+    window.analytics.track('Clicked', {
+        app: 'docs',
+        element: tracker.element ?? 'link',
+        button_text: anchor.textContent?.trim().slice(0, 200) || null,
+        href: url.href,
+        is_subdomain: isApifyDomain && url.hostname !== window.location.hostname,
+        is_outbound: !isApifyDomain,
+    });
+}
+
+function installLinkClickTracker() {
+    if (installed) return;
+    installed = true;
+
+    document.addEventListener('click', handleLinkClick, { capture: true });
+    document.addEventListener('auxclick', handleLinkClick, { capture: true });
+}
+
+export default ExecutionEnvironment.canUseDOM ? {
+    onRouteDidUpdate() {
+        installLinkClickTracker();
+    },
+} : null;