Switch camera during video call?

[Kulsum International Hospital]

i need to switch camera during video call . here is my code

this code run when video call connect

function initializeLocalMedia(options, callback) {

if (options) {
 options['audio'] = true;

 if (options['video'])
 options['video'] = true;
} else {
 options['audio'] = true;
 options['video'] = false;
}

navigator.mediaDevices.enumerateDevices().then(function (devices) {
 var cameras = [];
 devices.forEach(function (device) {
 'videoinput' === device.kind && cameras.push(device.deviceId);
 });
 
 var defaultsOpts = { audio: false, video: true }
 defaultsOpts.video = { facingMode: shouldFaceUser ? 'user' : 'environment' }
 var constraints = { video: { deviceId: { exact: cameras[1] } }, audio: true };

 navigator.mediaDevices.getUserMedia(defaultsOpts).then(function (_stream) {
 stream = _stream;

 window.localStream = stream;
 

 myapp.setMyVideo(window.localStream)
 if (callback)
 callback();
 }, function (err) {
 console.log("The following error occurred: " + err.name);
 alert('Unable to call ' + err.name)
 });


});

}

and this code for flip camera

flipBtn.addEventListener('click', function () {
 if (stream == null) return
// // we need to flip, stop everything
 stream.getTracks().forEach(t => {
 t.stop();
 });
// // toggle / flip
 shouldFaceUser = !shouldFaceUser;
// capture();
 var defaultsOpts = { audio: false, video: true }
 defaultsOpts.video = { facingMode: shouldFaceUser ? 'user' : 'environment' }
 //var constraints = { video: { deviceId: { exact: cameras[1] } }, audio: true };

 navigator.mediaDevices.getUserMedia(defaultsOpts).then(function (_stream) {

 stream = _stream;
 
 
 replaceTracks(stream);
 
 }, function (err) {
 console.log("The following error occurred: " + err.name);
 alert('Unable to call ' + err.name)
 });
 })

 function replaceTracks(newStreamm) {
 //console.log(window.RTCPeerConnection);
 detachMediaStream();

 newStreamm.getVideoTracks().forEach(function (track) {
 track.stop();
 });
 var configuration = {
 iceServers: [{ urls: "stun:stun.1.google.com:19302" }]
 };
 
 //var candidate = new RTCIceCandidate(msg.candidate);
 attachMediaStream(newStreamm);

 // optionally, if you have active peer connections:
 _replaceTracksForPeer();

 function _replaceTracksForPeer() {
 var pc = new RTCPeerConnection();

 // var tracks = newStream.getVideoTracks()[0];
 // tracks.enabled = true;
 pc.getSenders().map(function (sender) {
 sender.replaceTrack(newStreamm.getTracks().find(function (track) {
 return track.kind === sender.track.kind;
 }));
 });
 }
 }

 function detachMediaStream() {
 var elem = document.getElementById('my-video');
 //var elem = document.getElementById(id);

 if (elem) {
 elem.pause();

 if (typeof elem.srcObject === 'object') {
 elem.srcObject = null;
 } else {
 elem.src = '';
 }
 }
 };

 function attachMediaStream(newStreamm) {
 var elem = document.getElementById('my-video');

 if (elem) {
 if (typeof elem.srcObject === 'object') {
 elem.srcObject = newStreamm;
 } else {
 elem.src = window.URL.createObjectURL(newStreamm);
 }

 elem.onloadedmetadata = function (e) {
 elem.play();
 };
 } else {
 throw new Error('Unable to attach media stream');
 }
 };




when i click on flip button remote camera just hang and wont run again.