script.js

const video = document.querySelector('video')

const startVideo = () => {
    navigator.getUserMedia(
        { video: true },
        stream => video.srcObject = stream,
        err => console.error(err)
    )
}

Promise.all([
    faceapi.nets.tinyFaceDetector.loadFromUri('/models'),
    faceapi.nets.faceLandmark68Net.loadFromUri('/models'),
    faceapi.nets.faceRecognitionNet.loadFromUri('/models'),
    faceapi.nets.faceExpressionNet.loadFromUri('/models')
]).then(startVideo).catch(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)
})