RTCPeerConnection: canTrickleIceCandidates property
The read-only RTCPeerConnection
property canTrickleIceCandidates
returns a boolean value which indicates whether or not the remote peer can accept
trickled ICE candidates.
ICE trickling is the process of continuing to send candidates after the initial offer or answer has already been sent to the other peer.
This property is only set after having called
RTCPeerConnection.setRemoteDescription()
. Ideally, your signaling
protocol provides a way to detect trickling support, so that you don't need to rely on
this property. A WebRTC browser will always support trickle ICE. If trickling isn't
supported, or you aren't able to tell, you can check for a falsy value for this
property and then wait until the value of
iceGatheringState
changes to
"completed"
before creating and sending the initial offer. That way, the
offer contains all of the candidates.
Value
A boolean value that is true
if the remote peer can accept
trickled ICE candidates and false
if it cannot. If no remote peer has
been established, this value is null
.
Note: This property's value is determined once the local peer has
called RTCPeerConnection.setRemoteDescription()
; the provided
description is used by the ICE agent to determine whether or not the remote peer
supports trickled ICE candidates.
Examples
js
const pc = new RTCPeerConnection();
function waitToCompleteIceGathering(pc) {
return new Promise((resolve) => {
pc.addEventListener(
"icegatheringstatechange",
(e) =>
e.target.iceGatheringState === "complete" &&
resolve(pc.localDescription)
);
});
}
// The following code might be used to handle an offer from a peer when
// it isn't known whether it supports trickle ICE.
async function newPeer(remoteOffer) {
await pc.setRemoteDescription(remoteOffer);
const offer = await pc.createOffer();
await pc.setLocalDescription(offer);
if (pc.canTrickleIceCandidates) return pc.localDescription;
const answer = await waitToCompleteIceGathering(pc);
sendAnswerToPeer(answer); //To peer via signaling channel
}
// Handle error with try/catch
pc.addEventListener(
"icecandidate",
(e) => pc.canTrickleIceCandidates && sendCandidateToPeer(e.candidate)
);
Specifications
Specification |
---|
WebRTC: Real-Time Communication in Browsers # dom-rtcpeerconnection-cantrickleicecandidates |
Browser compatibility
BCD tables only load in the browser