vuex

index.js :

import Vue from 'vue';
import Vuex from 'vuex';
Vue.use(Vuex);

export default new Vuex.Store({
    state: {
        count: 2
    },
    getters: {
        todos: state => {
            return state += 5
        }
    }
})

main.js:

import Vue from 'vue'
import App from './App.vue'
import store from './store'

Vue.config.productionTip = false

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