RTCDataChannel: binaryType property

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

The property binaryType on the RTCDataChannel interface is a string which specifies the type of 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.

Value

A string 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.

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

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

  byteArray.forEach((byte) => {
    hexString += `${byte.toString(16)} `;
  });
};

Specifications

Specification
WebRTC: Real-Time Communication in Browsers
# dom-datachannel-binarytype

Browser compatibility

BCD tables only load in the browser

See also