fix: ensure undefined values are removed in cleanup

This fixes a crasher.

src/lib/parser/Deck.test.ts

@@ -0,0 +1,13 @@
+import Deck from './Deck';
+
+describe('Deck', () => {
+  test('undefined cards becomes empty array', () => {
+    const deck = new Deck('deck', undefined, undefined, '', 0, null);
+    expect(deck.cards).toStrictEqual([]);
+  });
+
+  test('handles cleaning undefined notes', () => {
+    const deck = new Deck('deck', [undefined], undefined, '', 0, null);
+    expect(Deck.CleanCards(deck.cards)).toStrictEqual([]);
+  });
+});

src/lib/parser/Deck.ts

@@ -4,7 +4,7 @@ import Settings from './Settings';
 export default class Deck {
   name: string;
 
-  cards: Note[];
+  cards: (Note | undefined)[];
 
   image: string | undefined;
 
@@ -20,27 +20,27 @@ export default class Deck {
 
   constructor(
     name: string,
-    cards: Note[],
+    cards: (Note | undefined)[],
     image: string | undefined,
     style: string | null,
     id: number,
     settings: Settings
   ) {
     this.settings = settings;
     this.name = name;
-    this.cards = cards;
+    this.cards = cards ?? [];
     this.image = image;
     this.style = style;
     this.id = id;
-    console.log(`New Deck with ${this.cards.length} cards`);
   }
 
-  static CleanCards(cards: Note[]) {
+  static CleanCards(cards: (Note | undefined)[]) {
     return cards.filter(
       (note) =>
-        note.isValidClozeNote() ||
-        note.isValidInputNote() ||
-        note.isValidBasicNote()
+        note &&
+        (note.isValidClozeNote() ||
+          note.isValidInputNote() ||
+          note.isValidBasicNote())
     );
   }