He usado esto para la detección de formas y he usado 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);