Added static classes to log progress and errors

src/js/utils/helpers.js

@@ -22,4 +22,20 @@ export default class Helpers {
       }
     };
   }
+
+  static logProgress() {
+    return function(xhr) {
+      if(xhr.lengthComputable) {
+        const percentComplete = xhr.loaded / xhr.total * 100;
+
+        console.log(Math.round(percentComplete, 2) + '% downloaded');
+      }
+    }
+  }
+
+  static logError() {
+    return function(xhr) {
+      console.error(xhr);
+    }
+  }
 }