how to list rooms on socket.io nodejs server

function ActiveRooms(){
var activeRooms = [];
Object.keys(io.sockets.adapter.rooms).forEach(room=>{
var isRoom = true;
Object.keys(io.sockets.adapter.sids).forEach(id=>{
isRoom = (id === room)? false: isRoom;
});
if(isRoom)activeRooms.push(room);
});
return activeRooms;}

in Socketio 2.0

to get rooms use

Object.keys(socket.adapter.rooms);

to get the room name

Object.keys(socket.adapter.rooms)[1];

Filtering out the 'real' rooms can be done like this:

var realRooms = Object.keys(io.sockets.adapter.rooms).reduce((filtered, key) => {
if(!io.sockets.adapter.rooms[key].sockets.hasOwnProperty(key)) filtered.push(key);
return filtered;
}, []);

According to the documentation of [Socket.io-v3.x][1], to get all current rooms created, you just simply do `socket.rooms`

```js
io.on('connection', socket => {

console.log(socket.rooms);
socket.on('disconnect', () => {
// socket.rooms.size === 0
});
});
```
and it return like this

```js
Set(2) {
'_y_xQeeF6PpFiPQqAAFC',
'6113cb71359644408895afcf6112df3c76981e3f88bc5c08'
}
```

[1]:https://socket.io/docs/v3/rooms/index.html#Disconnection

on v4 proceed like this:

Array.from(io.adapter.rooms.entries())
It will return an array with the keys (roomIds) and values (socketIds), same structure as Object.entries():

[
[roomId],[Set(2) {"socketId1","socketId2"}],
[roomId2], [Set(3) {"socketId3","socketId4","socketId5"}],
]

For socket v4. This works:

io.sockets.adapter.rooms.get("id of the room")

To obtain an array of strings that contains all rooms in v4 you can use:

// if you are not using namespaces
Array.from(io.of("/").adapter.rooms.keys());
// if you are using namespaces
Array.from(io.of("/your-namespace").adapter.rooms.keys());
// output: ["room1", "room2", ...]