RTCPeerConnection.canTrickleIceCandidates

読み取り専用の RTCPeerConnection プロパティ canTrickleIceCandidates は、リモート・ピアが trickled ICE 候補を受け入れることができるかどうかを示す Boolean を返します。

ICE トリックリングとは、最初のオファーや回答がすでに相手に送られた後も、候補者を送り続けるプロセスのことです。

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.

 var canTrickle = RTCPeerConnection.canTrickleIceCandidates;

A Boolean 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.

var pc = new RTCPeerConnection();
// The following code might be used to handle an offer from a peer when
// it isn't known whether it supports trickle ICE.
pc.setRemoteDescription(remoteOffer)
  .then(_ => pc.createAnswer())
  .then(answer => pc.setLocalDescription(answer))
  .then(_ =>
    if (pc.canTrickleIceCandidates) {
      return pc.localDescription;
    }
    return new Promise(r => {
      pc.addEventListener('icegatheringstatechange', e => {
        if (e.target.iceGatheringState === 'complete') {
          r(pc.localDescription);
        }
      });
    });
  })
  .then(answer => sendAnswerToPeer(answer)) // signaling message
  .catch(e => handleError(e));

pc.addEventListener('icecandidate', e => {
  if (pc.canTrickleIceCandidates) {
    sendCandidateToPeer(e.candidate); // signaling message
  }
});

• WebRTC
• RTCPeerConnection.addIceCandidate()
• Lifetime of a WebRTC session