Redux - Trying to add a function to configureStore

I'm the creator of Redux Toolkit. persistedState is not a valid configuration option for configureStore. The correct field name is preloadedState.

Instead of using configureStore use createStore. For me this works:

const store = createStore(
    reducer,
    persistedState
  );

full example:

  const loadFromLocalStorage = () => {
    try {
      const serializedState = localStorage.getItem('state');
      return JSON.parse(serializedState);
    } catch (e) {
      throw new Error(e)
    }
  };

  const saveToLocalStorage = state => {
    try {
      const serializedState = JSON.stringify(state);
      localStorage.setItem('state', serializedState);
    } catch (e) {
      throw new Error(e)
    }
  };

  const state= loadFromLocalStorage();


  const store = createStore(
    reducer,
    state
  );
  store.subscribe(() => {
    saveToLocalStorage(store.getState());
  });