fix(middleware/persist): Fix the storage type

[MOZGIII]

Related Issues

Went ahead with the PR, skipped the issue.

Summary

The storage must be operating with the persisted state type, which by default matches the state type. Otherwise it's not possible to introduce serialization/deserialization logic.

An example of how this would be useful:

export function createSerdeStorage<State, RawState>(
  serialize: (state: State) => RawState,
  deserialize: (rawState: RawState) => State,
  getStorage: () => PersistStorage<RawState>
): PersistStorage<State> {
  const storage = getStorage();
  return {
    getItem: async (name) => {
      const data = await storage.getItem(name);
      if (data === null) return null;
      return {
        ...data,
        state: deserialize(data.state),
      };
    },
    setItem: (name, value) =>
      storage.setItem(name, { ...value, state: serialize(value.state) }),
    removeItem: storage.removeItem,
  };
}

// An implementation of the custom deserializer for the timestamp with the above logic.
export function createTimestampStorage<State>(
  getStorage: () => PersistStorage<string>
): PersistStorage<State> {
  return createSerdeStorage<State, string>(
    JSON.stringify,
    Temporal.ZonedDateTime.from,
    getStorage
  );
}

Check List

• yarn run prettier for formatting code and docs

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[dai-shi]

Oh, you are right. I think I missed it when #1463 is developed.

[MOZGIII]

Note I also exported the StorageValue - it is required for a type-safe PersistStorage definitions in custom store implementations.

[dai-shi]

We generally avoid exporting type aliases, but because PersistStorage is an exported interface, exporting StorageValue seems rather fair.

[MOZGIII]

Exactly my point!