Vue 给mapState中定义的属性赋值报错的解决方案

时间:2020-06-20 22:01:00 来源:互联网 作者: 神秘的大神 字体:

Vue mapState中定义的属性赋值报错的解决方案

by:授客 QQ1033553122

1.   实践环境

Vue 2.9.6

 

2.   问题描述

<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>

 

如上,我们希望在执行increaseCount函数时,给mapstate函数中映射定义的this.count赋值,给该值增加1,结果,提示

[Vue warn]: Computed property "count" was assigned to but it has no setter.

 

3.   解决方案1

如下,把属性“移出mapState”,然后为属性新增get,set方法,分别用于获取值和改变值(按store状态管理规定的方式)

 

<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>

 

注意:this.$store.commit("increaseCount", val);中的increaseCount方法名称,并不是methods中定义的方法名称,而是store中定义的方法

 

4.   解决方案2

通过对比当前属性值和store状态值,然后根据比较结果,决定是否根据store状态管理规则更新状态值。

<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>