store.js

import Vue from 'vue'
import Vuex from 'vuex'
import { ui } from '@/plugins/firebaseui-init'
import { firebase } from '@/plugins/firebase-init'

Vue.use(Vuex)

const defaultState = {
    user: {
      uid: null,
      displayName: null,
      photoURL: null,
      email: null,
      phoneNumber: null,
    }
  };

const store = new Vuex.Store({
  state: defaultState,
  getters: {
    isAuthenticated: state => {
      return state.user.uid !== null;
    }
  },
  mutations: {
    user(state, userObj){
      state.user = {
        uid: userObj.uid,
        displayName: userObj.displayName,
        photoURL: userObj.photoURL,
        email: userObj.email,
        phoneNumber: userObj.email,
      }
    }

  },
  actions: {
    signOut: async ( { dispatch, commit } ) => {
      await firebase.auth().signOut();
      commit('user', defaultState);
      window.location.reload();
    }
  }
})

export default store;