vuex mounted中取不到mapState的值

`<template>
  <div class="home">
    vuex action
    <div>点击获取数据</div>
    <ul>
      <li v-for="(item, index) of voteData" :key="index">
        {{ item.title }}
      </li>
    </ul>
  </div>
</template>

<script>
import { mapState } from 'vuex'
const mapStateObj = mapState(['voteData'])
export default {
  name: 'Home',
  data () {
    return {
      a: []
    }
  },
  create () {
  },
  computed: {
    ...mapStateObj
  },
  mounted () {
    this.$store.dispatch('getVoteData')
    console.log(this.voteData)
    this.a = this.voteData
    console.log(this.a)
  },
  methods: {

  }
}
</script>
`