async function connect() {
  // set up an instance of the Ably realtime library
  const ably = new Ably.Realtime.Promise({ authUrl: '/api/createTokenRequest' });
  
  // create a channel called "tshirt"
  const channelId = "tshirt";
  
  //connect to the tshirt channel
  const channel = await ably.channels.get(channelId);
  await channel.attach();
  
  //subscribe to the channel to get updates and call processMessage
  channel.subscribe(processMessage);  
}

connect();