Fix: useranswer save/restore _index awareness (fixes #489) (#490)

Author: oliverfoster

js/models/itemsComponentModel.js

@@ -24,11 +24,13 @@ export default class ItemsComponentModel extends ComponentModel {
   restoreUserAnswers() {
     const booleanArray = this.get('_userAnswer');
     if (!booleanArray) return;
-    this.getChildren().forEach((child, index) => child.set('_isVisited', booleanArray[index]));
+    this.getChildren().forEach(child => child.set('_isVisited', booleanArray[child.get('_index')]));
   }
 
-  storeUserAnswer() {
-    const booleanArray = this.getChildren().map(child => child.get('_isVisited'));
+  storeUserAnswer() {    
+    const items = this.getChildren().slice(0);
+    items.sort((a, b) => a.get('_index') - b.get('_index'));
+    const booleanArray = items.map(child => child.get('_isVisited'));
     this.set('_userAnswer', booleanArray);
   }