script.js

const video = document.getElementById('video')
Promise.all([
    faceapi.nets.tinyFaceDetector.loadFromUri('/models'),
    // recognize all the different parts like eyes, mouth.. etc
    faceapi.nets.faceLandmark68Net.loadFromUri('/models'),
    faceapi.nets.faceRecognitionNet.loadFromUri('/models'),
    // recognize feelings like being happy, smiling, sad.. etc
    faceapi.nets.faceExpressionNet.loadFromUri('/models'),
]).then(startVideo)
function startVideo() {
    navigator.getUserMedia(
        { video: {}},
        stream => video.srcObject = stream,
        err => console.error(err)
    )
}
video.addEventListener('play',() => {
    const canvas = faceapi.createCanvasFromMedia(video)
    document.body.append(canvas)
    const displaySize = {
        width: video.width,
        height: video.height
    }
    faceapi.matchDimensions(canvas,displaySize)
    setInterval(async () => { 
        const detections = await faceapi.detectAllFaces(video,
             new faceapi.TinyFaceDetectorOptions()).
        withFaceLandmarks().withFaceExpressions()
        const resizedDetections = faceapi.resizeResults(detections, displaySize)
        canvas.getContext('2d').clearRect(0,0, canvas.width,canvas.height)
        faceapi.draw.drawDetections(canvas, resizedDetections)
        faceapi.draw.drawFaceLandmarks(canvas, resizedDetections)
        faceapi.draw.drawFaceExpressions(canvas, resizedDetections)
    },100)
})