Grabbed dndbeyond's source code

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

ddb_main/tools/js/Shared/managers/SpellsManagerContext.tsx

@@ -0,0 +1,26 @@
+import React, { useMemo } from "react";
+
+import {
+  getSpellsManager,
+  SpellsManager,
+} from "@dndbeyond/character-rules-engine/es";
+
+interface SpellsManagerContextValue {
+  spellsManager: SpellsManager;
+}
+
+const initContext: SpellsManagerContextValue = {
+  spellsManager: null!,
+};
+export const SpellsManagerContext =
+  React.createContext<SpellsManagerContextValue>(initContext);
+
+export function SpellsManagerProvider({ children }) {
+  // TODO: try getting the initialized sub and cleaning it up in here?
+  const spellsManager: SpellsManager = useMemo(() => getSpellsManager(), []);
+  return (
+    <SpellsManagerContext.Provider value={{ spellsManager }}>
+      {children}
+    </SpellsManagerContext.Provider>
+  );
+}