FIX: Looping attempt to reconnect in network connectivity service (#22783)

app/assets/javascripts/discourse/app/services/network-connectivity.js

@@ -1,5 +1,8 @@
 import Service from "@ember/service";
+import discourseDebounce from "discourse-common/lib/debounce";
 import { ajax } from "discourse/lib/ajax";
+import { bind } from "discourse-common/utils/decorators";
+import { cancel } from "@ember/runloop";
 import { tracked } from "@glimmer/tracking";
 
 const CONNECTIVITY_ERROR_CLASS = "network-disconnected";
@@ -14,28 +17,53 @@ export default class NetworkConnectivity extends Service {
 
     window.addEventListener("offline", () => {
       this.setConnectivity(false);
+      this.startTimerToCheckNavigator();
     });
 
-    window.addEventListener(
-      "online",
-      this.pingServerAndSetConnectivity.bind(this)
-    );
+    window.addEventListener("online", this.pingServerAndSetConnectivity);
 
-    window.addEventListener("visibilitychange", this.onFocus.bind(this));
+    window.addEventListener("visibilitychange", this.onFocus);
   }
 
+  @bind
   onFocus() {
     if (!this.connected && document.visibilityState === "visible") {
       this.pingServerAndSetConnectivity();
     }
   }
 
+  @bind
   async pingServerAndSetConnectivity() {
-    let response = await ajax("/srv/status", { dataType: "text" }).catch(() => {
-      this.setConnectivity(false);
-    });
+    try {
+      let response = await ajax("/srv/status", { dataType: "text" });
+      if (response === "ok") {
+        cancel(this._timer);
+        this.setConnectivity(true);
+      } else {
+        throw "disconnected";
+      }
+    } catch {
+      // Either the request didn't go out at all or the response wasn't "ok". Both are failures.
+      // Start the timer to check every second if `navigator.onLine` comes back online in the event that
+      // we miss the `online` event firing
+      this.startTimerToCheckNavigator();
+    }
+  }
 
-    this.setConnectivity(response === "ok");
+  @bind
+  startTimerToCheckNavigator() {
+    cancel(this._timer);
+
+    this._timer = discourseDebounce(this, this.checkNavigatorOnline, 1000);
+  }
+
+  @bind
+  checkNavigatorOnline() {
+    if (navigator.onLine) {
+      this.pingServerAndSetConnectivity();
+    } else {
+      this.startTimerToCheckNavigator();
+    }
   }
 
   setConnectivity(connected) {