RTCIceTransport: gatheringstatechange event

A gatheringstatechange event is sent to an RTCIceTransport when its ICE candidate gathering state changes. The gathering state, whose actual status can be found in the transport object's gatheringState property, indicates whether or not the ICE agent has begun gathering candidates, and if so, if it has finished doing so.

Bubbles No
Cancelable No
Interface Event
Event handler property ongatheringstatechange

The key difference between gatheringstatechange and icegatheringstatechange is that the latter represents the overall state of the connection including every RTCIceTransport used by every RTCRtpSender and every RTCRtpReceiver on the entire connection. In contrast, gatheringstatechange represents changes to the candidate gathering state for a single transport.

Examples

This example creates a handler for gatheringstatechange events on each RTCRtpSender associated with a given RTCPeerConnection. Here, the addEventListener() method is called to add a listener for gatheringstatechange events:

pc.getSenders().forEach(sender => {
  sender.transport.iceTransport.addEventListener("gatheringstatechange", ev => {
  let transport = ev.target;

  if (transport.gatheringState === "complete") {
    /* this transport has finished gathering candidates,
       but others may still be working on it */
  }
}, false);

Likewise, you can use the ongatheringstatechange event handler property:

pc.getSenders().forEach(sender => {
  sender.transport.iceTransport.ongatheringstatechange = ev => {
    let transport = ev.target;

    if (transport.gatheringState === "complete") {
      /* this transport has finished gathering candidates,
         but others may still be working on it */
    }
  };
});

Specifications

Specification Status Comment
WebRTC 1.0: Real-time Communication Between Browsers
The definition of 'gatheringstatechange' in that specification.
Candidate Recommendation  

Browser compatibility

Update compatibility data on GitHub
DesktopMobile
ChromeEdgeFirefoxInternet ExplorerOperaSafariAndroid webviewChrome for AndroidFirefox for AndroidOpera for AndroidSafari on iOSSamsung Internet
gatheringstatechange eventChrome No support NoEdge No support NoFirefox No support NoIE No support NoOpera No support NoSafari No support NoWebView Android No support NoChrome Android No support NoFirefox Android No support NoOpera Android No support NoSafari iOS No support NoSamsung Internet Android No support No

Legend

No support  
No support

See also