perf(core): Skip serialization for push messages with no recipients (#25308)

packages/cli/src/push/__tests__/websocket.push.test.ts

@@ -107,6 +107,13 @@ describe('WebSocketPush', () => {
 		expect(mockWebSocket2.send).toHaveBeenCalledWith(expectedMsg, { binary: false });
 	});
 
+	it('skips sending when user has no connections', () => {
+		webSocketPush.add(pushRef1, userId, mockWebSocket1);
+		webSocketPush.sendToUsers(pushMessage, ['nonexistent-user']);
+
+		expect(mockWebSocket1.send).not.toHaveBeenCalled();
+	});
+
 	it('emits message event when connection receives data', async () => {
 		jest.useRealTimers();
 		const mockOnMessageReceived = jest.fn();

packages/cli/src/push/abstract.push.ts

@@ -74,6 +74,8 @@ export abstract class AbstractPush<Connection> extends TypedEmitter<AbstractPush
 	}
 
 	private sendTo({ type, data }: PushMessage, pushRefs: string[], asBinary: boolean = false) {
+		if (pushRefs.length === 0) return;
+
 		this.logger.debug(`Pushed to frontend: ${type}`, {
 			dataType: type,
 			pushRefs: pushRefs.join(', '),