const store = new Vuex.Store({
    state: {
        count: 0
    },
    mutations: {
        increment: state => state.count++,
        decrement: state => state.count--
    }
})

const Counter = {
  template: `<div>{{ count }}</div>`,
  computed: {
    count () {
      return this.$store.state.count
    }
  }
}

Vue.component('counter',Counter)

const app = new Vue({
    el: '#app',
    store,
    computed: {
        count() {
            return store.state.count
        }
    },
    methods: {
        increment() {
            store.commit('increment')
        },
        decrement() {
            store.commit('decrement')
        }
    }
})