refactor: clean up parser and tests (#387)

* tests: improve coverage

* refactor: clean up nodes

* chore: lint

* feat(parser): ignore `BrandVideoShelf`

Seems to be used for ads.

* feat(parser): ignore `BrandVideoSingleton` too

src/parser/classes/MultiMarkersPlayerBar.ts

@@ -1,11 +1,10 @@
+import { YTNode, observe, type ObservedArray } from '../helpers.js';
+import type { RawNode } from '../index.js';
 import Parser from '../index.js';
 import Chapter from './Chapter.js';
 import Heatmap from './Heatmap.js';
-import type { RawNode } from '../index.js';
 
-import { observe, ObservedArray, YTNode } from '../helpers.js';
-
-class Marker extends YTNode {
+export class Marker extends YTNode {
   static type = 'Marker';
 
   marker_key: string;
@@ -14,23 +13,23 @@ class Marker extends YTNode {
     chapters?: Chapter[];
   };
 
-  constructor (data: RawNode) {
+  constructor(data: RawNode) {
     super();
     this.marker_key = data.key;
 
     this.value = {};
 
-    if (data.value.heatmap) {
+    if (Reflect.has(data.value, 'heatmap')) {
       this.value.heatmap = Parser.parseItem(data.value.heatmap, Heatmap);
     }
 
-    if (data.value.chapters) {
+    if (Reflect.has(data.value, 'chapters')) {
       this.value.chapters = Parser.parseArray(data.value.chapters, Chapter);
     }
   }
 }
 
-class MultiMarkersPlayerBar extends YTNode {
+export default class MultiMarkersPlayerBar extends YTNode {
   static type = 'MultiMarkersPlayerBar';
 
   markers_map: ObservedArray<Marker>;
@@ -39,10 +38,9 @@ class MultiMarkersPlayerBar extends YTNode {
     super();
     this.markers_map = observe(data.markersMap?.map((marker: {
       key: string;
-      value: { [key: string ]: any
-    }}) => new Marker(marker)) || []);
+      value: {
+        [key: string]: RawNode
+      }
+    }) => new Marker(marker)) || []);
   }
-}
-
-export { Marker };
-export default MultiMarkersPlayerBar;
+}