Modern facingMode
by Pranab Dey
HTML
<button onclick="stop();gum('user')">Front</button>
<button onclick="stop();gum('environment')">Back</button>
<div id="div"></div><br>
<video id="video" height="320" autoplay></video>
<script src="https://webrtc.github.io/adapter/adapter-latest.js"></script>
JavaScript
var gum = face =>
console.log('running');
navigator.mediaDevices.getUserMedia({video: {facingMode: {exact: face}}})
.then(stream => (video.srcObject = stream))
.catch(e => log(e));
var stop = () => video.srcObject && video.srcObject.getTracks().map(t => t.stop());
var log = msg => div.innerHTML += "<p>" + msg + "</p>";