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RTCSctpTransport: maxMessageSize property

The maxMessageSize read-only property of the RTCSctpTransport interface indicates the maximum size of a message that can be sent using the RTCDataChannel.send() method.

Value

An integer value giving the maximum size, in bytes, of a message which can be sent using the RTCDataChannel.send() method.

Examples

This example shows how you might split up a string into small enough parts to send based on maximum message size.

js

// Function splits strings to a specified size and returns array.
function splitStringToMax(str, maxLength) {
  const result = [];
  let i = 0;
  while (i < str.length) {
    result.push(str.substring(i, i + maxLength));
    i += maxLength;
  }
  return result;
}

const peerConnection = new RTCPeerConnection(options);
const channel = peerConnection.createDataChannel("chat");
channel.onopen = (event) => {
  const maximumMessageSize = peerConnection.sctp.maxMessageSize;
  const textToSend = "This is my possibly overly long string!";
  splitStringToMax(textToSend, maximumMessageSize).forEach((elem) => {
    channel.send(elem);
  });
};

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
maxMessageSize 76 79 113 No 63 15.4 76 76 113 54 15.4 12.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/API/RTCSctpTransport/maxMessageSize