script.js

const video = document.getElementById('video')

Promise.all([
 faceapi.nets.tinyFaceDetector.loadFromUri('/models'),
 faceapi.nets.faceLandmark68Net.loadFromUri('/models'),
 faceapi.nets.faceRecognitionNet.loadFromUri('/models'),
 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)
})