MediaStream: addtrack event

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2017.

The addtrack event is fired when a new MediaStreamTrack object has been added to a MediaStream.

This event is not cancelable and does not bubble.

Syntax

Use the event name in methods like addEventListener(), or set an event handler property.

addEventListener("addtrack", (event) => { })

onaddtrack = (event) => { }

Also inherits properties from its parent interface, Event.

MediaStreamTrackEvent.track Read only: A MediaStreamTrack object representing the track which was added to the stream.

Using addEventListener():

const stream = new MediaStream();

stream.addEventListener("addtrack", (event) => {
  console.log(`New ${event.track.kind} track added`);
});

Using the onaddtrack event handler property:

const stream = new MediaStream();

stream.onaddtrack = (event) => {
  console.log(`New ${event.track.kind} track added`);
};

Specification
Media Capture and Streams # event-mediastream-addtrack