react-redux-localStorage.js

// How to persist the React Redux state store to the browser's localStorage
// Code taken from Dan Abramov's video
// https://egghead.io/lessons/javascript-redux-persisting-the-state-to-the-local-storage

/**
  localStorage.js
  */
export const loadState = () => {
  try {
    const serializedState = localStorage.getItem('state');
    if (serializedState === null) {
      return undefined;
    }
    return JSON.parse(serializedState);
  } catch (error) {
    return undefined;
  }
};

export const saveState = (state) => {
  try {
    const serializedState = JSON.stringify(state);
    localStorage.setItem('state', serializedState);
  } catch (error) {
    console.log(error);
  }
};

/**
  index.js
  */
import { loadState, saveState } from './localStorage';

const store = createStore(reducers, loadState());

store.subscribe(() => {
  saveState(store.getState());
});

ReactDOM.render(
  <Provider store={store}>
    <App />
  </Provider>,
  document.getElementById('root'),
);