PhoenixSocket.swift

public func joinChannel(with channelId: String,
                        payload: Socket.Payload,
                        channelEventListeners: [ChannelEventListener],
                        onJoinSuccess: @escaping (Socket.Payload) -> (),
                        onJoinError: @escaping (Socket.Payload) -> ()) {
  
  guard let socket = socket else { return }
  
  let joinChannelBlock: () -> () = {[weak self] in
    
    guard
      let weakSelf = self
      else { return }
    
    let channel: Channel = socket.channel(channelId, payload: payload)
    
    //map listeners to channel
    for listener in channelEventListeners {
      channel.on(listener.event, callback: listener.callback)
    }
    
    channel.join()?
      .receive("ok", callback: onJoinSuccess)
      .receive("error", callback: onJoinError)
    
    weakSelf.channels[channelId] = channel
  }
  
  // Verify if the socket is connected
  if !socket.isConnected {
    connect(with: joinChannelBlock)
  } else {
    joinChannelBlock()
  }
}