Uncaught ReferenceError: Cannot access 'store' before initialization

I’m trying to get this working with an existing Vue 2 app but I’m getting the error:

Uncaught ReferenceError: Cannot access ‘store’ before initialization

I have a folder within:

src
  store
    index.js
    store.js
  main.js

main.js imports the store as such:

import store from './store/index.js';

and initialises the Vue instance like so:

export const app = new Vue({
  render: (h) => h(App),
  store,
  router,
  i18n,
}).$mount('#app');

index.js in the store folder looks like:

import Vue from 'vue';
import Vuex from 'vuex';
import { state, mutations, actions, getters } from './store.js';
import createPersistedState from 'vuex-persistedstate';

Vue.use(Vuex);

export default new Vuex.Store({
  state,
  mutations,
  actions,
  getters,
  plugins: [
    createPersistedState({
      storage: window.sessionStorage,
    }),
  ],
});

Am I doing something wrong?