RTCDataChannel.binaryType

The property binaryType on the RTCDataChannel interface is a DOMString which specifies the type of JavaScript object which should be used to represent binary data received on the RTCDataChannel. Values allowed by the WebSocket.binaryType property are also permitted here: "blob" if Blob objects are being used or "arraybuffer" if ArrayBuffer objects are being used. The default is "blob".

When a binary message is received on the data channel, the resulting message event's MessageEvent.data property is an object of the type specified by the binaryType.

Syntax

var type = aDataChannel.binaryType;

aDataChannel.binaryType = type; 

Value

A DOMString that can have one of these values:

"blob"

Received binary messages' contents will be contained in Blob objects.

"arraybuffer"

Received binary messages' contents will be contained in ArrayBuffer objects.

Example

This code configures a data channel to receive binary data in ArrayBuffer objects, and establishes a listener for message events which constructs a string representing the received data as a list of hexadecimal byte values.

var dc = peerConnection.createDataChannel("Binary");
dc.binaryType = "arraybuffer";

dc.onmessage = function(event) {
  let byteArray = new Uint8Array(event.data);
  let hexString = "";

  byteArray.forEach(function(byte) {
    hexString += byte.toString(16) + " ";
  });
};

Specifications

Browser compatibility

[1] The interface is called DataChannel and not RTCDataChannel in Firefox; however, a binding was added in Firefox 24 which allows either name to be used.

[2] Chrome currently only supports "arraybuffer"; "blob" is not yet supported.

See also

• WebRTC
• Using WebRTC data channels
• RTCDataChannel
• RTCDataChannel.send()