Reviving nested states from localstorage results in loss of part of nested initial state values

Suppose I have this initial state:

{ 
   someKey: {}
   itemResults: {
          items: [], 
          totalItems: 0,
          isListView: true
    },
   someOtherKey: {}
}

and I have this config:

localStorageSync({
    keys: [{itemResults: ['isListView']}],
    rehydrate: true
})

and I have this state being revived from localStorage:

{ 
   itemResults: {
       isListView: false
   }
}

Which means during @ngrx/store/init, since we only do a shallow merge of keys using Object.assign, I end up with the following state:

{ 
   itemResults: {
       isListView: false
   }
}

So basically if you use a nested key or keys, then that slice of state overrides the whole slice of initialState for the top level key. I was thinking it’d be nice if I could just use lodash’s merge to merge (or basically Object.assign nested keys also)<del>, but I don’t want to bloat this library either. It would be nice if I could supply a function to the library to use to do the merge, then I could just use lodash.merge there instead of bundling it with the library. </del>

<del>Could we possibly add a config option to allow the user to provide a custom merge function? Basically something like this?</del>

export const localStorageSync = (config: LocalStorageConfig) => (reducer: any) => {
    // ... code omitted

    const mergeFunction = config.customMergeFunction || ((state, rehydratedState) =>  Object.assign({}, state, rehydratedState));

    return function (state = rehydratedState, action: any) {
        
        if (action.type === INIT_ACTION && rehydratedState) {
            state = mergeFunction(state, rehydratedState);
        }
     
        // ... code omitted
    };
};

<del>Any thoughts/objections, anyone?</del>

---

EDIT: Renaming the thread since it appears that there’s a general consensus that a deep merge should be the default behavior here.

[adamkleingit]

I don’t really understand how this library is usable without fixing this. If I want to sync only part of the state, it makes sense that the rest of the initial state will not be changed by default. Unless I’m missing something

[vvolodin]

What is preventing this issue from being fixed for more than a year? Any help needed?