Really simple react hook for persistant reducer across session.

usePersistReducer.js

import { useReducer } from 'react';

export const usePersistReducer = (reducer, initialState, key) => {
  let persistKey = `__PERSIST_REDUCER_${key}__`
  const persistReducer = (state, action) => {
    let newState = reducer(state, action);

    localStorage.setItem(persistKey, JSON.stringify(newState));

    return newState;
  }

  let persistInitialState = localStorage.getItem(persistKey);
  
  if (!persistInitialState) {
    persistInitialState = initialState;
  } else {
    try {
      persistInitialState = JSON.parse(persistInitialState);
    } catch (err) {
      persistInitialState = initialState;
    }
  }

  return useReducer(persistReducer, persistInitialState);
}