fix: allow numeric rooms

The support for numeric rooms was lost when we used a Map for the
'rooms' property, which stores the relationships between Socket IDs and
rooms ([1]).

This commit restores the ability to use numbers as rooms:

```js
socket.join(42);

io.to(42).emit("hello");
```

Note: for proper TypeScript support, we should also update the type of
Room to `string | number`

[1]: socketio/socket.io-adapter@53ed3f4

Related: #418

lib/index.ts

@@ -29,6 +29,8 @@ interface Request {
   [other: string]: any;
 }
 
+const isNumeric = (str) => !isNaN(str) && !isNaN(parseFloat(str));
+
 export interface RedisAdapterOptions {
   /**
    * the name of the key to pub/sub events on as prefix
@@ -130,7 +132,7 @@ export class RedisAdapter extends Adapter {
     }
 
     const room = channel.slice(this.channel.length, -1);
-    if (room !== "" && !this.rooms.has(room)) {
+    if (room !== "" && !this.hasRoom(room)) {
       return debug("ignore unknown room %s", room);
     }
 
@@ -152,6 +154,12 @@ export class RedisAdapter extends Adapter {
     super.broadcast(packet, opts);
   }
 
+  private hasRoom(room): boolean {
+    // @ts-ignore
+    const hasNumericRoom = isNumeric(room) && this.rooms.has(parseFloat(room));
+    return hasNumericRoom || this.rooms.has(room);
+  }
+
   /**
    * Called on request from another node
    *

test/index.ts

@@ -14,6 +14,8 @@ let namespace1, namespace2, namespace3;
 let client1, client2, client3;
 let socket1, socket2, socket3;
 
+const shouldNotHappen = (done) => () => done(new Error("should not happen"));
+
 [
   {
     name: "socket.io-redis",
@@ -44,7 +46,7 @@ let socket1, socket2, socket3;
       socket2.broadcast.emit("woot", [], { a: "b" }, buf, array);
     });
 
-    it("broadcasts to rooms", (done) => {
+    it("broadcasts to a room", (done) => {
       socket1.join("woot");
       client2.emit("do broadcast");
 
@@ -66,6 +68,15 @@ let socket1, socket2, socket3;
       });
     });
 
+    it("broadcasts to a numeric room", (done) => {
+      socket1.join(123);
+      namespace2.to(123).emit("broadcast");
+
+      client1.on("broadcast", done);
+      client2.on("broadcast", shouldNotHappen(done));
+      client3.on("broadcast", shouldNotHappen(done));
+    });
+
     it("uses a namespace to broadcast to rooms", (done) => {
       socket1.join("woot");
       client2.emit("do broadcast");