feat: migrate all playlist renderers to TypeScript

src/parser/classes/PlaylistSidebar.ts

@@ -0,0 +1,20 @@
+import Parser from '../index';
+import { YTNode } from '../helpers';
+
+class PlaylistSidebar extends YTNode {
+  static type = 'PlaylistSidebar';
+
+  items;
+
+  constructor(data: any) {
+    super();
+    this.items = Parser.parse(data.items);
+  }
+
+  // XXX: alias for consistency
+  get contents() {
+    return this.items;
+  }
+}
+
+export default PlaylistSidebar;