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/InventoryManagerContext.tsx

@@ -0,0 +1,28 @@
+import React, { useContext, useMemo } from "react";
+
+import { InventoryManager } from "@dndbeyond/character-rules-engine/es";
+
+interface InventoryManagerContextValue {
+  inventoryManager: InventoryManager;
+}
+const initContext: InventoryManagerContextValue = {
+  inventoryManager: new InventoryManager(),
+};
+export const InventoryManagerContext =
+  React.createContext<InventoryManagerContextValue>(initContext);
+
+export function InventoryManagerProvider({ children }) {
+  const inventoryManager: InventoryManager = useMemo(
+    () => new InventoryManager(),
+    []
+  );
+  return (
+    <InventoryManagerContext.Provider value={{ inventoryManager }}>
+      {children}
+    </InventoryManagerContext.Provider>
+  );
+}
+
+export const useInventoryManager = () => {
+  return useContext(InventoryManagerContext);
+};