RTCDataChannel: close() method

The RTCDataChannel.close() method closes the RTCDataChannel. Either peer is permitted to call this method to initiate closure of the channel.

Closure of the data channel is not instantaneous. Most of the process of closing the connection is handled asynchronously; you can detect when the channel has finished closing by watching for a close event on the data channel.

The sequence of events which occurs in response to this method being called:

1. RTCDataChannel.readyState is set to closing.
2. A background task is established to handle the remainder of the steps below, and close() returns to the caller.
3. The transport layer deals with any buffered messages; the protocol layer decides whether to send them or discard them.
4. The underlying data transport is closed.
5. The RTCDataChannel.readyState property is set to closed.
6. If the transport was closed with an error, the RTCDataChannel is sent an error event with its name set to NetworkError.
7. A close event is sent to the channel.

close()

const pc = new RTCPeerConnection();
const dc = pc.createDataChannel("my channel");

dc.onmessage = (event) => {
  console.log(`received: ${event.data}`);
  dc.close(); // We decided to close after the first received message
};

dc.onopen = () => {
  console.log("datachannel open");
};

dc.onclose = () => {
  console.log("datachannel close");
};

// Now negotiate the connection and so forth…