vuex分模块后,实现获取state的值

//car.js
state = {
  list: []
}
getters = {
  carGetter: state => {
    return state.list.filter('');
  }
}
new Vuex.Store({
  getters: {
    test: state => {
      return '02';
    } 
  },
  modules: { car }  
})
// 组件
this.$store.state.car.list // OK
this.$store.state.car.carGetter // undefined
this.$store.state.carGetter // 为什么这么用ok, 难道会把模块中的getters注册到root ?

<template>
<div class="panel panel-info">
   <div class="panel-heading">
     <h4 class="panel-title">购物车列表</h4>
   </div>
   <div class="panel-body">
     <p v-if="!CartList.length">这里什么都没有，请先添加商品。</p>
     <CartListItem v-for="ele in CartList" :key="ele.id" :cartlist-iteam="ele"/>
   </div>
   <div class="panel-footer">
     <a href="" class="btn btn-block btn-danger">清空购物车（{{cartQuantity}}）</a>
     <a href="" class="btn btn-block btn-info">立即结算（{{cartTotal}}）</a>
   </div>
 </div>
</template>

<script>
import CartListItem from './CartListItem'
import { mapGetters } from 'vuex'
export default {
 name: 'CartList',
 components: {
  CartListItem
 },
 computed: {
  CartList () {
   return this.$store.state.cartModule.updateCartList
  },
  ...mapGetters(['cartQuantity', 'cartTotal'])
 }
}
</script>