解决Vue 给mapState中定义的属性赋值报错的问题

<script>
import { mapState } from 'vuex';
export default {
 name: "displayCount",
 computed: {
  ...mapState({
   ...略
   count: state => state.a.count
  })
 },
 methods: {
  increaseCount () {
   this.count = this.count + 1
  }
 }
};
</script>
<style>
</style>

<script>
import { mapState } from 'vuex';
export default {
 name: "displayCount",
 computed: {
  ...mapState({
...略
  }),
  count: {
   get() {
    return this.$store.state.a.count;
   },
   set(val) {
    this.$store.commit("increaseCount", val);
   }
  }
 },
 methods: {
  increaseCount () {
   this.count = this.count + 1
  }
 }
};
</script>

<script>
import { mapState } from 'vuex';
export default {
 name: "displayCount",
 computed: {
  ...mapState({
   count: state => state.a.count
  })
 },
 methods: {
  increaseCount () {
   if (this.count == this.$store.state.a.count) {
    this.$store.commit("increaseCount", this.count+1);
   }
  }
 }
};
</script>