报错unknown getter和unknown mutation type

Question

//mutations.js
import  getters from './getters'


const state={
    header:true
};

const mutations={
    showHeader(state){
        alert(2);
        state.header=true;
    },
    hideHeader(state){
        state.header=false;
    }
};

// const getters={
//     headerShow:(state)=>{
//         return state.header;
//     }
// }

export default{
    state,
    mutations,
    getters
}


//actions.js
export default{
    showHeader:({commit})=>{

        commit('showHeader')
    },
    hideHeader:({commit})=>{
        commit('hideHeader')
    }
}


//getter.js
export default{
    headerShow:(state)=>{
        alert(1);
        return state.header;
    }

}


//store.js
import Vue from 'vue'
import Vuex from 'vuex'

Vue.use(Vuex);

import mutations from './mutations.js'
import actions from './actions.js'

export default new Vuex.Store({
    modules:{
        mutations
    },
    actions
});


//app.vue
import {mapGetters,mapActions} from 'vuex'


export default {
  computed:mapGetters([
    'headerShow'
  ]),
  // mounted:function(){
  //   console.log(headerShow);
  // },
  watch:{
    $route(to,from){//当路由发生变化，触发此函数
      if(to.path=='/user-info'){
        this.$store.dispatch('hideHeader');
      }else{
        this.$store.dispatch('showHeader');
      }
    }
  },