Camera.js

var videoElement = undefined;
var videoSelect = undefined;
var cameras = [];

jQuery(document).ready(function(){
    jQuery('#btn-change-camera').on('click', function(){
        changeCamera(cameras);
    })

    
videoElement = document.querySelector('video');
videoSelect = document.querySelector('select#videoSource');

navigator.mediaDevices.enumerateDevices()
  .then(gotDevices).then(getStream(cameras)).catch(handleError);


});



function gotDevices(deviceInfos) {
  
  for (var i = 0; i !== deviceInfos.length; ++i) {
    var deviceInfo = deviceInfos[i];
    if (deviceInfo.kind === 'videoinput') {
      cameras.push(deviceInfo.deviceId);
    }
  }
}

function getStream(cameras) {
  if (window.stream) {
    window.stream.getTracks().forEach(function(track) {
      track.stop();
    });
  }

  var constraints = {
    video: {
      deviceId: {exact: cameras[0]}
    }
  };

  navigator.mediaDevices.getUserMedia(constraints).
    then(gotStream).catch(handleError);
}

function gotStream(stream) {
  window.stream = stream; // make stream available to console
  videoElement.srcObject = stream;
}

function handleError(error) {
  console.log('Error: ', error);
}

function changeCamera(camera) {
	var cameraToPush = cameras.shift()
	getStream(cameras)
	cameras.push(cameraToPush)
}