Migrate to gtag.js

js/application.js

@@ -12,7 +12,11 @@ window.requestAnimationFrame(function () {
     noticeClose.addEventListener("click", function () {
       notice.parentNode.removeChild(notice);
       storage.setNoticeClosed(true);
-      ga("send", "event", "notice", "closed");
+      if (typeof gtag !== undefined){
+        gtag("event", "closed", {
+          event_category: "notice",
+        });
+      }
     });
   }
 });

js/html_actuator.js

@@ -38,8 +38,10 @@ HTMLActuator.prototype.actuate = function (grid, metadata) {
 
 // Continues the game (both restart and keep playing)
 HTMLActuator.prototype.continueGame = function () {
-  if (typeof ga !== "undefined") {
-    ga("send", "event", "game", "restart");
+  if (typeof gtag !== "undefined") {
+    gtag("event", "restart", {
+      event_category: "game",
+    });
   }
 
   this.clearMessage();
@@ -133,8 +135,12 @@ HTMLActuator.prototype.message = function (won) {
   var type    = won ? "game-won" : "game-over";
   var message = won ? "You win!" : "Game over!";
 
-  if (typeof ga !== "undefined") {
-    ga("send", "event", "game", "end", type, this.score);
+  if (typeof gtag !== "undefined") {
+    gtag("event", "end", {
+      event_category: "game",
+      event_label: type,
+      value: this.score,
+    });
   }
 
   this.messageContainer.classList.add(type);