Report WebSocket errors that occur after construction

Author: shepmaster

ui/frontend/websocket.ts

@@ -1,23 +1,27 @@
+async function reportWebSocketError() {
+  try {
+    await fetch('/nowebsocket', {
+      method: 'post',
+      headers: {
+        'Content-Length': '0',
+      },
+    });
+  } catch (e) {
+    console.log('Error:', e);
+  }
+}
+
 export default function openWebSocket(currentLocation: Location) {
   try {
     const wsProtocol = currentLocation.protocol === 'https:' ? 'wss://' : 'ws://';
     const wsUri = [wsProtocol, currentLocation.host, '/websocket'].join('');
-    return new WebSocket(wsUri);
+    const ws = new WebSocket(wsUri);
+    ws.addEventListener('error', () => reportWebSocketError());
+    return ws;
   } catch {
     // WebSocket URL error or WebSocket is not supported by browser.
     // Assume it's the second case since URL error is easy to notice.
-    (async () => {
-      try {
-        await fetch('/nowebsocket', {
-          method: 'post',
-          headers: {
-            'Content-Length': '0',
-          },
-        });
-      } catch (e) {
-        console.log('Error:', e);
-      }
-    })();
+    reportWebSocketError();
     return null;
   }
 }