feat: handle pre-rendering

modules/index.js

@@ -112,9 +112,21 @@ function addCWVTracking() {
 function addNavigationTracking() {
   // enter checkpoint when referrer is not the current page url
   const navigate = (source, type, redirectCount) => {
+    // target can be 'visible', 'hidden' (background tab) or 'prerendered' (speculation rules)
     const payload = { source, target: document.visibilityState };
-    // reload: same page, navigate: same origin, enter: everything else
-    if (type === 'reload' || source === window.location.href) {
+    if (document.prerendering) {
+      // listen for "activation" of the current pre-rendered page
+      document.addEventListener('prerenderingchange', () => {
+        // pre-rendered page is now "activated"
+        payload.target = 'prerendered';
+        sampleRUM('navigate', payload); // prerendered navigation
+      }, {
+        once: true,
+      });
+      if (type === 'navigate') {
+        sampleRUM('prerender', payload); // prerendering page
+      }
+    } else if (type === 'reload' || source === window.location.href) {
       sampleRUM('reload', payload);
     } else if (type && type !== 'navigate') {
       sampleRUM(type, payload); // back, forward, prerender, etc.