presentation-api/receiving-ua/support/PresentationConnection_send_receiving-ua.html

<!DOCTYPE html>

<meta charset="utf-8">
<title>Sending a message through PresentationConnection</title>
<link rel="author" title="Tomoyuki Shimizu" href="https://github.com/tomoyukilabs/">
<link rel="help" href="http://w3c.github.io/presentation-api/#sending-a-message-through-presentationconnection">
<script src="../common.js"></script>
<script src="stash.js"></script>

<script>
const stash = new Stash(stashIds.toReceiver, stashIds.toController);

navigator.presentation.receiver.connectionList.then(list => {
  const connection = list.connections[0];

  const message1 = '1st';
  const message2 = '2nd';
  const message3 = new Uint8Array([51, 114, 100]);      // "3rd"
  const message4 = new Uint8Array([52, 116, 104]);      // "4th"
  const message5 = new Uint8Array([108, 97, 115, 116]); // "last"

  // send messages
  return stash.receive().then(() => {
    connection.send(message1);              // string
    connection.send(message2);              // string
    connection.send(new Blob([message3]));  // Blob
    connection.send(message4.buffer);       // ArrayBuffer
    connection.send(message5);              // ArrayBufferView

    return stash.receive();
  }).then(() => {
    // try to send a message in the "closed" state
    // Note: a receiving user agent does not fire a "terminate" event
    connection.close();
    connection.onclose = () => {
      try {
        connection.send(message1);
        stash.send(JSON.stringify({ type: 'ok' }));
      } catch (e) {
        stash.send(JSON.stringify({ type: 'error', name: e.name, message: e.message }));
      }
    };
  });
});
</script>