How to get all clients connected to a specific namespace socket.io v.4

[raphael10-collab]

To get all the clients connected to a specific namespace, I tried to do this:

import { Server } from 'socket.io'

export const getClients = (io: Server, nsp: string) => new Promise((r, j) => {
  io.of(nsp).clients((error, client) => (error ? j(error) : r(client)))
})

But I'm getting this error:

error TS2339: Property 'clients' does not exist on type 'Namespace<DefaultEventsMap, 
DefaultEventsMap, DefaultEventsMap>'.

16   io.of(nsp).clients((error, client) => (error ? j(error) : r(client)))
                ~~~~~~~

And actually it seems there is not clients property: https://socket.io/docs/v4/namespaces/#main-namespace

node : v14.15.5

How to get all clients connected to a specific namespace socket.io v.4.2.0 ?