add analytics

app/src/services/analytics/NetworkDetector.js

@@ -0,0 +1,30 @@
+export class NetworkDetector {
+  constructor() {
+    this.isOnline = navigator.onLine;
+    this.listeners = [];
+  }
+
+  subscribe(listener) {
+    this.listeners.push(listener);
+
+    window.addEventListener('online', () => {
+      this.isOnline = true;
+      this.listeners.forEach(l => l(true));
+    });
+
+    window.addEventListener('offline', () => {
+      this.isOnline = false;
+      this.listeners.forEach(l => l(false));
+    });
+
+    return () => {
+      this.listeners = this.listeners.filter(l => l !== listener);
+    };
+  }
+
+  getStatus() {
+    return this.isOnline;
+  }
+}
+
+export const networkDetector = new NetworkDetector();