QR camera

qrcam.js

const video = document.createElement("video"),
    canvasElement = document.getElementById("qr-canvas"),
    canvas = canvasElement.getContext("2d"),
    outputData = document.getElementById("docqrcode"),
    btnScanQR = document.getElementById("take-camera");
let scanning = !1;

function tick() {
    canvasElement.height = video.videoHeight, canvasElement.width = video.videoWidth, canvas.drawImage(video, 0, 0, canvasElement.width, canvasElement.height), scanning && requestAnimationFrame(tick)
}

function scan() {
    try {
        qrcode.decode()
    } catch (e) {
        setTimeout(scan, 300)
    }
}
qrcode.callback = e => {
    if (e) {
        document.fullscreenElement && (document.exitFullscreen ? document.exitFullscreen() : document.mozCancelFullScreen ? document.mozCancelFullScreen() : document.webkitCancelFullScreen ? document.webkitCancelFullScreen() : document.msExitFullscreen && document.msExitFullscreen());
        const n = e.split("/");
        outputData.value = n[n.length - 1], scanning = !1, video.srcObject.getTracks().forEach((e => {
            e.stop()
        })), canvasElement.hidden = !0, document.getElementById("formvalidation").submit()
    }
}, btnScanQR.onclick = () => {
    navigator.mediaDevices.getUserMedia({
        video: {
            facingMode: "environment"
        }
    }).then((function(e) {
        document.querySelector('meta[name="viewport"]').setAttribute("content", "width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0,"), scanning = !0, canvasElement.hidden = !1, canvasElement.requestFullscreen ? canvasElement.requestFullscreen() : canvasElement.webkitRequestFullscreen ? canvasElement.webkitRequestFullscreen() : canvasElement.msRequestFullscreen && canvasElement.msRequestFullscreen(), video.srcObject = e, video.play(), tick(), scan()
    }))
};