fix(javascript): flush queued events after WebSocket reconnect

packages/javascript/src/modules/socket.ts

@@ -111,7 +111,10 @@ export default class Socket<T extends CatcherMessageType = 'errors/javascript'>
     if (this.ws === null) {
       this.eventsQueue.push(message);
 
-      return this.init();
+      await this.init();
+      this.sendQueue();
+
+      return;
     }
 
     switch (this.ws.readyState) {
@@ -218,6 +221,7 @@ export default class Socket<T extends CatcherMessageType = 'errors/javascript'>
       await this.init();
 
       log('Successfully reconnected.', 'info');
+      this.sendQueue();
     } catch (error) {
       this.reconnectionAttempts--;
 

packages/javascript/tests/socket.test.ts

@@ -4,6 +4,17 @@ import type { CatcherMessage } from '@hawk.so/types';
 
 const MOCK_WEBSOCKET_URL = 'ws://localhost:1234';
 
+/**
+ * vi.fn() replacement has no WebSocket.OPEN/CLOSED; Socket uses them in switch — without this,
+ * `undefined === undefined` always hits the first `case WebSocket.OPEN` and reconnect never runs.
+ */
+function patchWebSocketMockConstructor(ctor: { CONNECTING?: number; OPEN?: number; CLOSING?: number; CLOSED?: number }): void {
+  ctor.CONNECTING = 0;
+  ctor.OPEN = 1;
+  ctor.CLOSING = 2;
+  ctor.CLOSED = 3;
+}
+
 type MockWebSocket = {
   url: string;
   readyState: number;
@@ -72,3 +83,94 @@ describe('Socket', () => {
     expect(WebSocketConstructor).toHaveBeenCalledTimes(2);
   });
 });
+
+/**
+ * Regression: queued events must be flushed after reconnect / init, not only on first constructor connect.
+ */
+describe('Socket — events queue after connection loss', () => {
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  function mockWebSocketFactory(sockets: MockWebSocket[], closeSpy: ReturnType<typeof vi.fn>) {
+    const ctor = vi.fn<(url: string) => void>().mockImplementation(function (
+      this: MockWebSocket,
+      url: string
+    ) {
+      this.url = url;
+      this.readyState = WebSocket.CONNECTING;
+      this.send = vi.fn();
+      this.close = closeSpy;
+      this.onopen = undefined;
+      this.onclose = undefined;
+      this.onerror = undefined;
+      this.onmessage = undefined;
+      sockets.push(this);
+    });
+    patchWebSocketMockConstructor(ctor);
+
+    return ctor;
+  }
+
+  it('should flush queued event after reconnect when socket is CLOSED', async () => {
+    const sockets: MockWebSocket[] = [];
+    const closeSpy = vi.fn(function (this: MockWebSocket) {
+      this.readyState = WebSocket.CLOSED;
+      this.onclose?.({ code: 1001 } as CloseEvent);
+    });
+
+    const WebSocketConstructor = mockWebSocketFactory(sockets, closeSpy);
+    globalThis.WebSocket = WebSocketConstructor as unknown as typeof WebSocket;
+
+    const socket = new Socket({
+      collectorEndpoint: MOCK_WEBSOCKET_URL,
+      reconnectionTimeout: 10,
+    });
+
+    const ws1 = sockets[0];
+    ws1.readyState = WebSocket.OPEN;
+    ws1.onopen?.(new Event('open'));
+    await Promise.resolve();
+
+    ws1.readyState = WebSocket.CLOSED;
+
+    const payload = { type: 'errors/javascript', title: 'queued-after-drop' } as unknown as CatcherMessage<'errors/javascript'>;
+    const sendPromise = socket.send(payload);
+
+    const ws2 = sockets[1];
+    expect(ws2).toBeDefined();
+    ws2.readyState = WebSocket.OPEN;
+    ws2.onopen?.(new Event('open'));
+    await sendPromise;
+
+    expect(ws2.send).toHaveBeenCalledTimes(1);
+    expect(ws2.send).toHaveBeenCalledWith(JSON.stringify(payload));
+  });
+
+  it('should flush queued event when ws is null after pagehide and send()', async () => {
+    const closeSpy = vi.fn(function (this: MockWebSocket) {
+      this.readyState = WebSocket.CLOSED;
+      this.onclose?.({ code: 1000 } as CloseEvent);
+    });
+
+    const sockets: MockWebSocket[] = [];
+    const WebSocketConstructor = mockWebSocketFactory(sockets, closeSpy);
+    globalThis.WebSocket = WebSocketConstructor as unknown as typeof WebSocket;
+
+    const socket = new Socket({ collectorEndpoint: MOCK_WEBSOCKET_URL });
+    sockets[0].readyState = WebSocket.OPEN;
+    sockets[0].onopen?.(new Event('open'));
+    await Promise.resolve();
+
+    window.dispatchEvent(new Event('pagehide'));
+
+    const queued = { foo: 'bar' } as unknown as CatcherMessage<'errors/javascript'>;
+    const sendPromise = socket.send(queued);
+    sockets[1].readyState = WebSocket.OPEN;
+    sockets[1].onopen?.(new Event('open'));
+    await sendPromise;
+
+    expect(sockets[1].send).toHaveBeenCalledTimes(1);
+    expect(sockets[1].send).toHaveBeenCalledWith(JSON.stringify(queued));
+  });
+});