Web/API/RTCDataChannel/readyState

This is an experimental technologyCheck the Browser compatibility table carefully before using this in production.

The read-only RTCDataChannel property readyState returns an enum of type RTCDataChannelState which indicates the state of the data channel's underlying data connection.

Syntax

var state = aDataChannel.readyState;

Values

A string which is one of the values in the RTCDataChannelState enum, indicating the current state of the underlying data transport.

RTCDataChannelState enum

The RTCDataChannelState enum defines string constants which reflect the current status of the RTCDataChannel's underlying data connection.

Constant	Description
`"connecting"`	The user agent (browser) is in the process of creating the underlying data transport; that is, whatever network level connection is used to link the two peers together is in the process of being set up. This is the state of a new `RTCDataChannel` after being created by `RTCPeerConnection.createDataChannel()` (on the peer which started the connection process).
`"open"`	The underlying data transport has been established and data can be transferred bidirectionally across it. This is the default state of a new `RTCDataChannel` created by the WebRTC layer when the remote peer created the channel and delivered to the site or app in a `datachannel` event of type `RTCDataChannelEvent`.
`"closing"`	The process of closing the underlying data transport has begun. It is no longer possible to queue new messages to be sent, but previously queued messages may still be send or received before entering the `"closed"` state.
`"closed"`	The underlying data transport has closed, or the attempt to make the connection failed.

Example

var dataChannel = peerConnection.createDataChannel("File Transfer");
var sendQueue = [];

function sendMessage(msg) {
  switch(dataChannel.readyState) {
    case "connecting":
      console.log("Connection not open; queueing: " + msg);
      sendQueue.push(msg);
      break;
    case "open":
      sendQueue.forEach((msg) => dataChannel.send(msg));
      break;
    case "closing":
      console.log("Attempted to send message while closing: " + msg);
      break;
    case "closed":
      console.log("Error! Attempt to send while connection closed.");
      break;
  }
}

Specifications

Specification	Status	Comment
WebRTC 1.0: Real-time Communication Between BrowsersThe definition of 'RTCDataChannel.readyState' in that specification.	Candidate Recommendation	Initial specification.

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`readyState` Experimental'	Chrome Full support 56	Edge Full support ≤79	Firefox Full support Yes	IE No support No	Opera Full support 43	Safari No support No	WebView Android Full support 56	Chrome Android Full support 56	Firefox Android Full support Yes	Opera Android Full support 43	Safari iOS No support No	Samsung Internet Android Full support 6.0

Legend

Full support: Full support
No support: No support
Experimental. Expect behavior to change in the future.': Experimental. Expect behavior to change in the future.