Add GA4 tracking for SPA search visibility

src/assets/js/reprodb-profile.js

@@ -154,6 +154,11 @@ var ReproDBProfile = (function() {
       }
       history.pushState(null, '', url);
       showShare();
+      ReproDB.trackViewSearchResults({
+        searchTerm: (result.displayValue !== undefined ? result.displayValue : searchBox.value),
+        resultsCount: 1,
+        context: 'profile'
+      });
     }
 
     searchBox.addEventListener('input', function() {

src/assets/js/reprodb-search.js

@@ -110,6 +110,11 @@
     doSort();
     updateUrl();
     renderResults();
+    ReproDB.trackViewSearchResults({
+      searchTerm: cleaned,
+      resultsCount: filtered.length,
+      context: 'landing'
+    });
   }
 
   function doSort() {

src/assets/js/reprodb-utils.js

@@ -218,6 +218,51 @@
     return url;
   };
 
+  /* ─── Analytics helpers (GA4) ───────────────────────────────────── */
+
+  // Avoid flooding GA when the same search term is emitted repeatedly
+  // (e.g., URL updates and debounced input landing in close succession).
+  R._lastSearchEvent = { key: '', ts: 0 };
+
+  /**
+   * Emit a GA4 site-search signal for client-side (SPA-like) searches.
+   * opts.searchTerm   (required)  - user-entered query string
+   * opts.resultsCount (optional)  - number of matched results
+   * opts.context      (optional)  - logical source (landing/profile)
+   */
+  R.trackViewSearchResults = function(opts) {
+    if (typeof window.gtag !== 'function') return false;
+    opts = opts || {};
+
+    var searchTerm = (opts.searchTerm || '').trim();
+    if (!searchTerm) return false;
+
+    var context = (opts.context || 'search').trim();
+    var key = context + '|' + searchTerm.toLowerCase();
+    var now = Date.now();
+    if (R._lastSearchEvent.key === key && now - R._lastSearchEvent.ts < 1500) return false;
+    R._lastSearchEvent = { key: key, ts: now };
+
+    var eventParams = { search_term: searchTerm };
+    if (opts.resultsCount != null) {
+      var n = Number(opts.resultsCount);
+      if (!isNaN(n)) eventParams.results_count = n;
+    }
+    if (context) eventParams.search_context = context;
+
+    window.gtag('event', 'view_search_results', eventParams);
+
+    // In SPA flows, URL changes via history API do not automatically create
+    // page_view events; send one so GA4 reports align with the current URL.
+    window.gtag('event', 'page_view', {
+      page_title: document.title,
+      page_location: window.location.href,
+      page_path: window.location.pathname + window.location.search
+    });
+
+    return true;
+  };
+
   /* ─── Country / continent geo maps (shared across pages) ──────────── */
 
   R.CODE_TO_NAME = {