diff --git a/src/index.ts b/src/index.ts
index 65cc345..c6d4720 100755
--- a/src/index.ts
+++ b/src/index.ts
@@ -80,7 +80,7 @@ try {
 
     socket.on("disconnecting", async () => {
       socketDebug(`${socket.id} has disconnected`);
-      for (const roomID in socket.rooms) {
+      for (const roomID of socket.rooms) {
         const otherClients = (await io.in(roomID).fetchSockets()).filter(
           (_socket) => _socket.id !== socket.id,
         );
diff --git a/tsconfig.json b/tsconfig.json
index a239fb1..c4007dc 100755
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -1,6 +1,6 @@
 {
   "compilerOptions": {
-    "target": "es5",
+    "target": "es2020",
     "lib": ["dom", "dom.iterable", "esnext"],
     "allowJs": true,
     "skipLibCheck": true,