Fix 'WebSocket is not defined'

frontend/util/wsutil.ts

@@ -1,27 +1,42 @@
 // Copyright 2025, Command Line Inc.
 // SPDX-License-Identifier: Apache-2.0
 
-import type { WebSocket as NodeWebSocketType } from "ws";
+// In browser builds `window` is defined and the global `WebSocket` constructor is
+// available. When running inside the Electron *main* process (Node context),
+// `window` is undefined and we must fall back to the `ws` npm package.
 
-let NodeWebSocket: typeof NodeWebSocketType = null;
+// Import only the *type* from `ws`; the actual module will be required lazily
+// to avoid bundling issues when this file is transpiled for the renderer.
+import type { WebSocket as NodeWebSocketType } from "ws";
 
-if (typeof window === "undefined") {
-    // Necessary to avoid issues with Rollup: https://github.com/websockets/ws/issues/2057
-    import("ws")
-        .then((ws) => (NodeWebSocket = ws.default))
-        .catch((e) => {
-            console.log("Error importing 'ws':", e);
-        });
-}
+// Lazily initialised reference to the Node-side WebSocket constructor.
+let NodeWebSocket: typeof NodeWebSocketType | null = null;
 
 type ComboWebSocket = NodeWebSocketType | WebSocket;
 
-function newWebSocket(url: string, headers: { [key: string]: string }): ComboWebSocket {
-    if (NodeWebSocket) {
+function newWebSocket(
+    url: string,
+    headers?: { [key: string]: string } | null
+): ComboWebSocket {
+    // Node / Electron main process path ─ use `ws` package.
+    if (typeof window === "undefined") {
+        if (!NodeWebSocket) {
+            // `require` ensures the module is loaded synchronously to avoid the
+            // timing issue that caused "WebSocket is not defined" errors when
+            // the previous asynchronous dynamic import had not completed yet.
+            // eslint-disable-next-line @typescript-eslint/no-var-requires
+            // @ts-ignore – CommonJS require is available in Node context.
+            const wsMod = require("ws") as typeof NodeWebSocketType | {
+                default: typeof NodeWebSocketType;
+            };
+            NodeWebSocket = (wsMod as any).default ?? (wsMod as any);
+        }
+        // At this point NodeWebSocket is guaranteed to be initialised.
         return new NodeWebSocket(url, { headers });
-    } else {
-        return new WebSocket(url);
     }
+
+    // Browser / renderer path ─ use the global WebSocket.
+    return new WebSocket(url);
 }
 
 export { newWebSocket };