vuex获取state对象中值的方法

// main.js中，把store注册在根实例下，可使用this.$stroe.state直接取值
export default {
  computed: {
    testNum() {
      return this.$store.state.testNum;
    }
  }
};

import { mapState } from "vuex";export default {
  data() {
    return { localNum: 1 };
  },
  computed: {
    ...mapState({
      // 箭头函数使代码更简练
      testNum1: state => state.testNum1,
      // 传字符参数'testNum2' 等价于 'state => state.testNum2'
      testNum2: "testNum2",
      // 组件的局部变量与Vuex变量相加
      testNum3(state) {
        return state.testNum1 + this.localNum;
      }
    }),
    ...mapState([
      // 映射this.testNum3为store.state.testNum3
      "testNum3"
    ])
  }
};

import { mapState } from "vuex";
export default {
  computed: {
    ...mapState({
      // 箭头函数使代码更简练
      testNum1: state => state.moduleA.testNum1
    }),
    // 第一个参数是namespace命名空间，填上对应的module名称即可
    ...mapState("moduleA", {
      testNum2: state => state.testNum2,
      testNum3: "testNum3"
    }),
    ...mapState("moduleA",[
      "testNum4"
    ])
  }
};

<h1>姓名：{{msg}}</h1>
<h1>年龄：{{age}}</h1>
<h1>数字：{{num}}</h1>
<input type="text" v-model="num">
computed: {
        age:function(){  //msg也相同，就没写
            return this.$store.state.age
        },
        num:{
            get:function(){
                return this.$store.state.num;
            },
            set:function(num){   //数据双向绑定
                this.$store.commit('setNum',num)
            }
        }
    },

<h1>姓名：{{msg}}</h1>
<h1>年龄：{{age}}</h1>
<h1>数字：{{num}}</h1>
<input type="text" :value="num" @input="changeVal" >
import { mapState } from 'vuex'  //需要引入mapState
computed:mapState(['age','msg','num']),
    methods: {  
        changeVal(e){    //设置值
            return this.$store.commit('setNum',e.target.value)
        }
    },

<h1>姓名：{{msg}}</h1>
<h1>年龄：{{age}}</h1>
<h1>数字：{{num}}</h1>
import { mapState } from 'vuex'  //需要引入mapState
computed:mapState({
        msg:'msg',
        num:'num',
        // age:(state)=>state.age,   //不需要大括号的时候，就不需要用 return 返回值
        age:(state)=>{ return state.age},
    })

<h1>姓名：{{msg}}</h1>
<h1>年龄：{{age}}</h1>
<h1>数字：{{num}}</h1>
import { mapState } from 'vuex'
let objMapState=mapState({
        msg:'msg',
        num:'num',
        // age:(state)=>state.age,
        age:function(state){ return this.greenColor+state.age},
    })
data() {
        return {
            greenColor:'blue'            
        }
    },
computed:{
        ...mapState(objMapState)
    }