I have used this for shape detection and used OpenCV lib

`let classifier = new cv.CascadeClassifier();
            let utils = new Utils('errorMessage');
            let faceCascadeFile = 'haarcascade_frontalface_default.xml'; // path to xml
            utils.createFileFromUrl(faceCascadeFile, faceCascadeFile, () => {
                    console.log('2133333333')

            classifier.load(faceCascadeFile); // in the callback, load the cascade from file
            console.log(classifier.load(faceCascadeFile),'..........load',faceCascadeFile);