Grabbed dndbeyond's source code

```
~/go/bin/sourcemapper -output ddb -jsurl https://media.dndbeyond.com/character-app/static/js/main.90aa78c5.js
```

ddb_main/hooks/useExtras.ts

@@ -0,0 +1,26 @@
+import { useContext, useEffect, useState } from "react";
+
+import {
+  ExtraManager,
+  FeaturesManager,
+} from "@dndbeyond/character-rules-engine/es";
+
+import { ExtrasManagerContext } from "~/tools/js/Shared/managers/ExtrasManagerContext";
+
+//TODO: need to look at subscribeToUpdates for how many times its being called on state updates
+export function useExtras() {
+  const { extrasManager } = useContext(ExtrasManagerContext);
+
+  const [extras, setExtras] = useState<Array<ExtraManager>>(
+    extrasManager.getCharacterExtraManagers()
+  );
+
+  useEffect(() => {
+    const onUpdate = () => {
+      setExtras(extrasManager.getCharacterExtraManagers());
+    };
+    return FeaturesManager.subscribeToUpdates({ onUpdate });
+  }, [extrasManager]);
+
+  return extras;
+}