example2.js

const pc = new RTCPeerConnection()

// 1. addTrack(audioTrack1)
const sender1 = pc.addTrack(audioTrack1)

// 2. negotiate
const offer1 = await pc.createOffer()
await pc.setLocalDescription(offer1)
await pc.setRemoteDescription(answer1)

// 3. removeTrack(sender1)
pc.removeTrack(sender1)

// 4. negotiate
const offer2 = await pc.createOffer()
await pc.setLocalDescription(offer2)
await pc.setRemoteDescription(answer2)

// 5. addTrack(audioTrack2)
//
// The following does not hold, so create a new RTCRtpTransceiver:
//
//    o The sender has never been used to send. More precisely, the
//      RTCRtpTransceiver associated with the sender has never had a
//      currentDirection of sendrecv or sendonly.
// 
const sender2 = pc.addTrack(audioTrack2)

// 6. negotiate
//
// `offer3` contains two m= sections, and `pc.getTransceivers()`
// contains two RTCRtpTransceivers.
const offer3 = await pc.createOffer()
await pc.setLocalDescription(offer3)
await pc.setRemoteDescription(answer3)