add event listener to video element in image classifier

Author: cvalenzuela

src/ImageClassifier/index.js

@@ -101,17 +101,17 @@ class ImageClassifier {
     await tf.nextFrame();
 
     // Classify the image using the selected model
-    if (this.video) {
-      if (this.video.readyState >= 2) {
+    /* eslint arrow-body-style: 0 */
+    if (this.videoElt && !this.addedListener) {
+      /* eslint func-names: 0 */
+      this.video.addEventListener('onloadstart', function () {
         return this.model.classify(imgToPredict, numberOfClasses).then((predictions) => {
           if (callback) {
             callback(predictions);
           }
         });
-      }
-      if (callback) {
-        callback([]);
-      }
+      });
+      this.addedListener = true;
     }
     return this.model.classify(imgToPredict, numberOfClasses).then((predictions) => {
       if (callback) {