From 13aae6933d65acfbbf2a1c7d6188894324fa4ed4 Mon Sep 17 00:00:00 2001
From: Jarred Sumner <jarred@jarredsumner.com>
Date: Thu, 28 Nov 2024 00:40:17 -0800
Subject: [PATCH] Fixes #15470

---
 src/bun.js/api/server.zig                      |  4 ++++
 test/js/bun/websocket/websocket-server.test.ts | 10 ++++++++++
 2 files changed, 14 insertions(+)

diff --git a/src/bun.js/api/server.zig b/src/bun.js/api/server.zig
index ef38c02e8b..fcf5935338 100644
--- a/src/bun.js/api/server.zig
+++ b/src/bun.js/api/server.zig
@@ -5765,6 +5765,10 @@ pub fn NewServer(comptime NamespaceType: type, comptime ssl_enabled_: bool, comp
                 return JSValue.jsNumber(0);
             }
 
+            if (this.config.websocket == null or this.app == null) {
+                return JSValue.jsNumber(0);
+            }
+
             return JSValue.jsNumber((this.app.?.numSubscribers(topic.slice())));
         }
 
diff --git a/test/js/bun/websocket/websocket-server.test.ts b/test/js/bun/websocket/websocket-server.test.ts
index 6bcb231747..53d2288b56 100644
--- a/test/js/bun/websocket/websocket-server.test.ts
+++ b/test/js/bun/websocket/websocket-server.test.ts
@@ -825,3 +825,13 @@ async function connect(server: Server): Promise<void> {
   clients.push(client);
   await promise;
 }
+
+it("you can call server.subscriberCount() when its not a websocket server", async () => {
+  const server = serve({
+    port: 0,
+    fetch(request, server) {
+      return new Response();
+    },
+  });
+  expect(server.subscriberCount("boop")).toBe(0);
+});