RTCTrackEventInit.streams

The RTCTrackEventInit dictionary's optional streams property provides an array containing a MediaStream object for each of the streams associated with the event's track.

var trackEventInit = {
  receiver: rtpReceiver,
  track: mediaStreamTrack,
  streams: [videoStream],
  transceiver: rtpTransceiver
};

var streamList = trackEventInit.streams;

An array of MediaStream objects, one for each stream which make up the track.

If streams is not specified, its default value is an empty array.