<div id="app">
		  <p>{{ count }}</p>
		  <p>
		    <button @click="increment">+</button>
		    <button @click="decrement">-</button>
		  </p>
		</div>
		<script src="vue/vue.js"></script>
		<script src="vue/vuex.js"></script>
		<script>
			const store =new Vuex.Store({
				state:{
					count:0
				},
				mutations:{
					increment:state =>state.count++,
					decrement:state =>state.count--
				}
			})
			var app =new Vue({
				el:‘#app‘,
				computed:{
					count(){
						return store.state.count
					}	
				},
				methods:{
					increment:function(){
						store.commit(‘increment‘);  // 到vuex里面做业务逻辑
					},
					decrement:function(){
						store.commit(‘decrement‘);
					}
				}
				
			})