umami/redux/store.js

import { useMemo } from 'react';
import { configureStore } from '@reduxjs/toolkit';
import thunk from 'redux-thunk';
import rootReducer from './reducers';

let store;

export function getStore(preloadedState) {
  return configureStore({
    reducer: rootReducer,
    middleware: [thunk],
    preloadedState,
  });
}

export const initializeStore = preloadedState => {
  let _store = store ?? getStore(preloadedState);

  // After navigating to a page with an initial Redux state, merge that state
  // with the current state in the store, and create a new store
  if (preloadedState && store) {
    _store = getStore({
      ...store.getState(),
      ...preloadedState,
    });
    // Reset the current store
    store = undefined;
  }

  // For SSG and SSR always create a new store
  if (typeof window === 'undefined') return _store;
  // Create the store once in the client
  if (!store) store = _store;

  return _store;
};

export function useStore(initialState) {
  return useMemo(() => initializeStore(initialState), [initialState]);
}