subscribe() function in mediasoup sample

client.js

async function subscribe() {
  const data = await socket.request('createConsumerTransport', {
    forceTcp: false,
  });

  if (data.error) {
    console.error(data.error);
    return;
  }

  const transport = device.createRecvTransport(data);
  const onNewStream = consume(transport);
  transport.on('connect', ({ dtlsParameters }, callback, errback) => {
    socket
      .request('connectConsumerTransport', {
        transportId: transport.id,
        dtlsParameters,
      })
      .then(callback)
      .catch(errback);
  });

  transport.on('connectionstatechange', async state => {
    switch (state) {
      case 'connecting':
        $txtSubscription.innerHTML = 'subscribing...';
        $fsSubscribe.disabled = true;
        break;

      case 'connected':
        const stream = await onNewStream;
        document.querySelector('#remote_video').srcObject = stream;
        $txtSubscription.innerHTML = 'subscribed';
        $fsSubscribe.disabled = true;
        break;

      case 'failed':
        transport.close();
        $txtSubscription.innerHTML = 'failed';
        $fsSubscribe.disabled = false;
        break;

      default:
        break;
    }
  });

  await onNewStream;
  socket.request('resume');
}