CODEBASE: Add Jsonable Map and Set types, move player.sourceFiles to a map (#473)

src/Types/Jsonable.ts

@@ -0,0 +1,20 @@
+import type { IReviverValue } from "../utils/JSONReviver";
+// Jsonable versions of builtin JS class objects
+export class JSONSet<T> extends Set<T> {
+  toJSON(): IReviverValue {
+    return { ctor: "JSONSet", data: Array.from(this) };
+  }
+  static fromJSON(value: IReviverValue): JSONSet<any> {
+    return new JSONSet(value.data);
+  }
+}
+
+export class JSONMap<K, V> extends Map<K, V> {
+  toJSON(): IReviverValue {
+    return { ctor: "JSONMap", data: Array.from(this) };
+  }
+
+  static fromJSON(value: IReviverValue): JSONMap<any, any> {
+    return new JSONMap(value.data);
+  }
+}