Start using GA4 (#2111)

src/telemetry/ga.js

@@ -1,8 +1,12 @@
 export const googleAnalytics = (gaID) => {
-  (function(i,s,o,g,r,a,m){i['GoogleAnalyticsObject']=r;i[r]=i[r]||function(){
-  (i[r].q=i[r].q||[]).push(arguments)},i[r].l=1*new Date();a=s.createElement(o),
-  m=s.getElementsByTagName(o)[0];a.async=1;a.src=g;m.parentNode.insertBefore(a,m)
-  })(window,document,'script','https://www.google-analytics.com/analytics.js','ga');
+  const script = document.createElement('script');
+  script.src = `https://www.googletagmanager.com/gtag/js?id=${gaID}`;
+  script.async = true;
+  document.head.appendChild(script);
 
-  ga('create', gaID, 'auto');
-};
+  window.dataLayer = window.dataLayer || [];
+  function gtag(){dataLayer.push(arguments);}
+  gtag('js', new Date());
+
+  gtag('config', gaID);
+};

src/telemetry/index.js

@@ -58,11 +58,11 @@ export function initializeTelemetry() {
  * @param {string} path The current page path.
  */
 export function submitPageViewTelemetry(path) {
-  // Send telemetry to Google Analytics.
-  if (window.ga) {
-    // `ga` will not be set if not using google analytics
-    ga("set", "page", path);
-    ga("send", "pageview");
+  // Send page view event to GA4.
+  if (window.gtag) {
+    window.gtag("event", "page_view", {
+      page_path: path,
+    });
   }
 
   // Use the standard events.